So, in canon, Earth had at least 4 colonies by 2150, and Andoria had quite the territory, infringing on Vulcan borders. The former's obviously crazy overpowered, but the current situation of all Federation founders aside Vulcan starting with just their homeworld is a bit off and causes some problems.
Here's my recommendations for additions to the start of some empires:

For United Earth:
Start with colony ships researched (it makes no canon sense and it starts researched in vanilla now for a reason).
Two fledgling colonies in the Alpha Centauri and Vega systems (two of the three colonies canon to ENT aside of Terra Nova). The latter would really help with making the Tellarites want to coalition up with UE instead of the Saurians or Denobulans or even the Tzenkethi sometimes.
Two outposts, one in the beta quadrant and one in the "Deneva" system. The former would be for placing Cold Station 12 so it doesn't end up at, like, P'Jem if it happens post-federation. Latter would be for colonization, and a stepping stone to Vega.

For Andoria:
Fledgling colony to the west (like 82 G. Eridani) so they're not far behind in colonization.
Outpost on a system halfway between Vulcan and P'Jem and east a bit, which should have Paan Mokar/Weytahn as a colonizable world.
Outpost on a system a bit north to explain why Vulcans didn't attack from that direction when they were scared about Xindi-derived weapons.

For others:
Tellarites could really use a few outposts, and the Vulcans could use another colony besides P'Jem (maybe at Kapteyn's Star).

Additionally, the Orions tend to expand like crazy westardly. I think a good way to limit this would be to create a minor empire for Coridan so it can act as its canon role of being an Orion-friendly, but also Federation-friendly, mediator that doesn't join the Federation for a long while.