Since we all know that Op/Grim/Bee/Windblade and Megs/Star/Shadow/Shockwave won't be all of them.

I'm going to put in guesses for both sides, and this is pure speculation.

Autobots:
Hot Rod. The connection made in TLK is something I actually like; make Bumblebee and Hot Rod buddies who counterbalance each other but can still play off others well. Plus we know Hot Rod has an Evergreen design
Prowl. He's overdue an appearance and it'd be nice to see him opposite a certain Decepticon
Hound. Popular in AoE/TLK, and his original personality would still work with the boisterous army truck; make him a humvee with a 'I can get anywhere' mentality and that's a solid base

Decepticons:
Soundwave. With the quartet of Lazerbeak, Ravage, Rumble, and Frenzy. Again; known evergreen design so they have a good base to work from. Plus he could easily be a 'ringer' brought in to provide a shift from 'Bumblebee on the run' to 'How do we finish the mission under his gaze'
Barricade. Because an evil police car who uses that to pin Bumblebee in place would make for a good episode, and he's a fan-favorite
Blackout or Lugnut. We just need a counter to Grimlock honestly, and a big ol' aircraft fits that bill.

I only did three each as... I figure that would be stretching it quite a bit as-is for a character focused show.

 

Easy :
Ratchet, Sideswipe, Prowl, Sunstreaker, Jetfire, Ironhide, Hound, Mirage.. .
Thundercracker, Skywarp, Soundwave, Ravage, Laserbeak. .

In short: all the usual geewun guys.
Pardon my cynicism, but that's how it's gonna be.

 

The Other Dinobots (Slug, Sludge, Swoop, Snarl, Slash, Scorn), Cliffjumper, Hot Rod, Arcee, Cheetor (being some Beast era characters in it), Ratchet, Ironhide, Drift, & Prowl.

The Constructicons/Devastator, Soundwave (with Rumble, Frenzy, Buzzsaw, Laserbeak, Ravage, Ratbat), Skywarp, Thundercracker, Lockdown, Tarantulas, & Tidal Wave