The enemy does not properly attack the base:

If you don't have a vehicle factory, most of the units like the main battle tank are hidden:

The enemy does not properly attack the base:

It's not a bug: the yuruki forces just stays at the colony to defense against any incoming synapol attack. They detected some signs of movement where the player is, but they have no clue. But maybe that at some point, they should attack the player?

If you don't have a vehicle factory, most of the units like the main battle tank are hidden:

What's the problem? You want me to allow the player to order units with the initial factory prerequisite?

The problem is that with initial trade platform before factory is that vehicles are invisible and not greyed out because in a regular match that build order is not possible.

The problem is that with initial trade platform before factory is that vehicles are invisible and not greyed out because in a regular match that build order is not possible.

What should I do: remove the factory prerequisites or give the player a factory in the starting buildings? Or make so that they appear grayed?

If you remove the factory prerequisites, you create inconsistent game rules compared to multiplayer matches. Either remove the trade platform or make the prerequisites visible. Otherwise, players are irritated and might think that units have been disabled, which some missions do.

Fixed everything you said!