If you’re mercenaries, your probably a generalist force, but you could possibly specialize. At 3050 the weight distribution is still probably close to 30/40/20/10 for Light/Medium/Heavy/Assault. So a light, 2 mediums, and a heavy as a starting idea.
For generalist:
Griffin and Wolverine are good ideas. Fast with some ranged firepower means you can disengage more easily when it goes to piss. For am light mech, I’d consider a Valkyrie. Fast enough for recon, fast enough to run. The LRM10 and decent armor means it can be an active participant in a medium/heavy mech fight.
A third medium or a heavy mech would either be a new CN9-D centurion, a dragon, or a QuickDraw. Those could all keep pace with the rest of your lance.
Now you’d have a lance with a minimum walk of 5, and if you take the QuickDraw, they all have a jump of 5. Lastly, they all have the ability to engage at range. Nobody is useless if your sniping at the enemy before closing range