I'd say yes it's overpowered.
First off, assuming I read your writeup correctly and you're not making other adjustments, you're substituting standard Ranger abilities from 12th(PF)/13th(3.5), 17th and 20th levels with abilities from level 5, 10 and 15. This means they get this power earlier.
Even if the abilities were equivalent, this would be unbalancing however I believe the abilities you give are stronger.
Also, since you say 3 things it's replacing I am assuming Spirit Hunter Rangers get all other "normal" ranger abilities not specified here. If that's untrue and they just get these 3 then my answer 180s.
Wolf vs Camouflage: Camouflage is based around special terrain picked so is situational. Depending on your campaign this may not matter (you may have 2 terrains ever and always be camouflaged) but one thing is certain, Wolf as written is anytime. As pointed out elsewhere, invis is WAY better than any hide (giving you essentially +20 to hide). The counterbalances are it's a limited number of rounds a day and that number is likely to be fairly low.
Hide in Plain Sight vs Hawk: Rangers have no class ability to fly. Hide in Plain comparitively is not a great feature IMO for rangers. Sniping never really came into a lot of love except for rogues that I've experienced; the ability to hide without anything around you in front of someone would be better served just shooting the enemy a bunch of times OR doing a full round melee (depending on your build). So if you're not using it to attack, you're using it to retreat in which case fly can serve the same purpose. If using it to retreat, the handlessness also doesn't matter that much. The counterbalance is hide would save you AOOs if retreating (however also has a counter check against it - fly does not). Also the fly is again a limited amount of rounds. Note, I also feel like fly is OP in itself (though part of the game). It allows you an extreme advantage over anything without fly and can allow you to bypass things entirely.
For both these abilities removed, you're also assuming the ranger hides at all. You've substituted things that benefit one skill with things that can be used by any ranger.
5th Favored Enemy vs Bear: Each favored enemy gives +2 damage and +2 skills against an enemy picked and an additional +2 vs one of the other favored. For ease let's call this +4. Bear basically gives whirlwind attack (feat) as well as +2 to hit on a touch attack (which at 15th level, seems very likely to hit) with a knockback that also basically stuns (if staggered and prone, you can stand and be restored to your original status 10' away:P) with no save. It also gives reach which "normal" bears (non-dire/non-advanced bears do not have). Anyway, to me +2&souped up feat way outweighs +4. This is also unbalanced to Fighters who would basically just get Whirlwind Attack (IF they had the prereqs). Counterbalance: This isn't as useful for archers unless they're caught up in melee then it's super useful for archers. Also, you could argue that with the shared pool of spirits per day this is probably defensive. That being said that argument potentially ignores the rest of the party...several classes/combos/feats would benefit greatly from having prone/staggered enemies, for example. The limit per day also brings this closer in line with whirlwind attack (which presumably you could do infinitely) however since it's so much better as well as affects 1 enemy (whirlwind attack on 1 enemy is basically an attack/no use) I'd still say better.
I also find unless your campaign is having folks fight the same monster type over and over that iterative damage bonuses can be "ok" (but mean nothing if you've picked the wrong type). I further believe that the genres of monsters could have been loosened some for rangers making favored enemy even weaker. Now granted if you're only fighting elves the additional "guarenteed +" is awesome. All that said, still don't think it's likely more awesome than Bear.
But ultimately, maybe the Q you need to answer is are rangers balanced/of average power. If your answer is no, then your changes may not be overpowered, they may just be making up for something. If your answer is yes (as mine would be), then I imagine your question and my answer are justified.
Disclaimer: Almost all my experience is with 3.5 D&D (not Pathfinder).
PS (semi-tangent): Not meant offensively, but when I think of wolf, I do not think invis and when I think of bear I don't not think whirlwind touch knockback attack.