No, they won’t
Spells reward dedication massively. Low-level spells very, very rarely matter at high levels—and when they do, they are the kind of utility stuff that doesn’t have to interact with creatures’ defenses or the action economy. That describes almost none of the spells you have selected.
Furthermore, the kinds of spells I describe, that would be good? Those kinds of spells are also good to get in the form of magic items. Use Magic Device is a great skill that rogues get, and well worth the skill points. Using magic items (including an innate affinity for using magic items, which is a valid way to describe your Use Magic Device bonus) to get your low-level utility spells is far more efficient than taking a level of a spellcasting class. High-level characters have a lot of money, and access to a lot of magical equipment, so spending a few hundred or even a few thousand gold pieces on these kinds of items is far, far less expensive than spending a level. A rogue is very strongly advised to carry a lot of magical utility gear.
- Ray of Frost - a few ranged-touch sneak attacks per day
Ranged sneak attacks are difficult to pull off if you aren’t building around them. Flanking is by-far the easiest way to achieve a sneak attack, and you cannot flank with ranged attacks. Moreover, leveraging sneak attack is all about applying it as much as possible—rogues use archery or dual-wielding because those things give lots and lots of attacks, allowing lots and lots of sneak attack. By high levels, dealing your sneak attack damage only once is not impressive, and not how you want to spend your turn.
- Shield - survive a few minutes in the middle of melee
Shield lasts far too little time, for far too little benefit. Non-touch AC has very little value in Pathfinder, particularly at high levels, and is not worth investing in—and casting shield is a big investment since you cannot simply cast it at the beginning of the day and forget about it.
- Draconic claws - a few rounds of no-penalty two-weapon fighting per day
You will have magic weapons at high levels, so these potentially represent a huge loss of damage. The attack penalty when using two-weapon fighting (assuming a light offhand weapon) is rather minor at high levels. Not worth it unless you expect to be stripped of your equipment often in your campaign.
- True Strike for occasional impossible hits
True strike is a pure trap. Anything you need true strike to hit, you don’t want to be hitting—you want to be running away from it. True strike takes up a turn, and then only applies to one attack—again, a single instance of sneak attack damage is not a lot at high levels. When you use true strike, you are basically saying that you are going to spend two turns getting one attack in—when in two turns you might get 12 attacks. Against something with a high enough AC that the need to hit justifies reducing your potential damage by 92%, that isn’t going to be worth anything. Anything with AC that high is out of your league.
- Expeditious Retreat for all kinds of situations
Except, not really. Speed boosts aren’t actually that good in Pathfinder—most of the time you want to stay with your party, so you can’t move faster than the slowest member, and in combat, it’s relatively rare that distances are large enough to justify it.
That said, expeditious retreat is still a better choice than the others. There could be cases where you want it. Not as often as you think, seems to me, but they will happen. I am not at all sure that’s true of, say, shield or true strike.
- plus Dancing Lights, Detect Magic, Mage Hand, etc.
These are honestly better than your other suggestions—these are legitimate utility tools that may actually find use.
So I plan to take the Minor Magic and Major Magic rogue talents, plus one level of draconic sorcerer after that.
This is redundant; minor magic and major magic are pretty bad talents, and the only reason you would take them is if it allows you to avoid multiclassing in the first place. If you are multiclassing anyway, skip these talents and get better ones. A single level of any spellcasting class does more than these talents do.
If you really want to make a more magical rogue, I strongly recommend getting more magic than this. A small smattering of low-level spells will only be a hindrance later on in the game. Having decent spellcasting, on the other hand, can be great. For instance, you could use the arcane trickster prestige class (which is core), which grants both spellcasting and sneak attack—it hurts your skills some, and your talents a lot, but it still works out a whole lot better since you can end up with a lot of spellcasting. Similarly, the eldritch scoundrel archetype (which is not core, but for the record) trades a lot of skills, talents, and sneak attack for spellcasting. But those kinds of costs are what spellcasting demands to be really relevant.
If you are more interested in being mostly a rogue with just a tiny selection of spells, you’re better off just sticking with magic items. If you absolutely need magic of your own, then use the magic talents. Multiclassing in Pathfinder comes with some pretty hefty costs, and those low-level spells aren’t really going to be worth it.
But if you still insist on dipping sorcerer, then you need much more utility—focus on spells that allow you to do more things, particularly out-of-combat things, rather than attempting to gain a combat advantage there—you won’t find one. Some better low-level spells, just for examples:
Cantrips:
Dancing lights, detect magic, mage hand—All good choices; don’t want you thinking that they aren’t if they don’t appear here. Detect magic in particular.
Acid splash—near-useless in combat, but out of combat you can get a lot of utility out of acid splash, by using it on objects. Acid will eat through locks, chests, doors, even walls if you use enough, and since cantrips are at-will, if you’ve got the time you can apply enough acid. Notably, since you need to use so much acid to get through tough objects, this is one of the few cases where actually having the sorcerer level is distinctly and substantially superior to using a magic item or rogue talent, since only a proper spellcaster gets the cantrips at will.
Ghost sound—A decent way to supply a distraction. Basically a vastly improved version of the old “throw a rock over there to make some noise away from your position” trope.
Message—Decent-enough, stealthy-enough communication at a distance. Quite solid.
1st-level spells:
Reduce person—excellent for infiltration, can open up a lot of new doors that you can’t use otherwise.
Disguise self—Obvious applications.
Grease—Probably the best 1st-level spell in the game. We have a whole Q&A on it. Vastly better if you can boost your caster level, however; perhaps ask your GM if you guys can start using traits, so you can take the Magical Knack trait? It would certainly fit your character. Note that you will have to ask your GM about how balancing does or doesn’t work with respect to becoming flat-footed and thus getting sneak attack. Also note that at high levels, between flying foes and the lack of time to cast a standard-action spell, you will eventually use this much less.
Magic aura—Hide the magic you’re using. Comes up kind of rarely and I’d prefer it in a wand or something, but still.
Mount—A much longer-lasting speed boost than expeditious retreat; less useful in combat but again, combat usage shouldn’t be your goal here.
Summon monster—Nearly useless with CL 1st, but if you, for instance, took the Magical Knack trait to boost your caster level, could be like a weaker bag of tricks. But then, you could just buy a bag of tricks...
Ventriloquism—Basically an improved ghost sound, useful for the same reasons that ghost sound is.
