Battletech

Generally they're not litigious about it, but make sure you don't name them identically. Most people name them something similar. Rifleman becomes Musketeer or Gunman, the Centurion become the Hoplite or Legionnaire, etc. Then use 'compatible with Battletech or other 1:285 scale mech games' as keywords to get noticed.

It would be very nice if CGL had something like Hero Forge, where you can plug in what your custom mini has and get a model that accurately portrays what weapons it has. Then you pay the company like $5 for an STL file and a liscence for personal use, and you can print that mini as much as you like.

A company will always say that making bootlegs of their products is illegal, especially if they're being sold.

In practice, they probably won't care or do anything about it if it isn't in large volumes.