This is going to be difficult to balance because bounded accuracy exists in 5e, and does not in 3.5.
The reasons you're going to run into serious problems with this is that 5th edition uses bounded accuracy. What this means is that there's a lower and upper limit on things like stats, saving throws, and skill checks.
For example: If you're using customizable stats, you can not have a score lower than 8 or higher than 15 before racial bonuses.
And except in extremely specific scenarios (like Barbarian or magic items), your maximum ability score is 20, even with racial and class bonuses.
If you're using random rolls to assign stats to your character's race, you're going to need to take into consideration the specific traits associated with each race and apply hard caps accordingly. Example, an Ogre has a trait called Legendary Stupidity. So even if you rolled 18 in INT, you'd still have trouble counting to 10 with your fingers in front of you, are prone to believing anything you're told, and are easily confused. This is traded off by their incredible Strength. So if I was to create a PC Ogre race, they'd get +4 to Strength as well as an increase maximum Strength comparable to a Barbarian (max of 24, and yes a Barbarian Ogre would then have a cap of 28 as it levelled), and a hard cap of 8 Intelligence to account for these. But this is what I mean when I say you have a lot of work ahead of you in trying to port these over effectively.
If you're going to try to make these fit, my recommendation is to use the stats from the Monster Manual as a direct translation of how strong that race should be when starting. Now, this is going to result in some disappointing races, as well as some incredibly overpowered ones.
The bottom line is that there is no easy way to translate 3.5 to 5. They don't run off the same foundation, so it's like trying to balance Warhammer with Scrabble.