GalaxyScenarioDef in your GameInfo folder is what has the template for the pirate base.
Find this: planetItemTypeCount
All the PITS/designName is what appears in the template. entityDefName is the actual entity file in GameInfo that the designName spawns.
You can change any template you want. Adjust the normal and quick start for more ships, structures, etc...
Find "Template:PirateBase"
These are the Titans available.
planetItemType
designName "Phase:Titan:Loyalist"
entityDefName "TITAN_PHASELOYALIST"
planetItemType
designName "Phase:Titan:Rebel"
entityDefName "TITAN_PHASEREBEL"
planetItemType
designName "Psi:Titan:Loyalist"
entityDefName "TITAN_PSILOYALIST"
planetItemType
designName "Psi:Titan:Rebel"
entityDefName "TITAN_PSIREBEL"
planetItemType
designName "Tech:Titan:Loyalist"
entityDefName "TITAN_TECHLOYALIST"
planetItemType
designName "Tech:Titan:Rebel"
entityDefName "TITAN_TECHREBEL"
just copy/paste one of the Titans designName (in bold) for the "Pirate:Frigate:Heavy". items 106 won't change since you are just replacing one item for another. You might be able to add more than 1 without issue.
You can give the pirates anything -avoid giving them cannons, they might actually use them.
Enjoy.
PS. subtract 40 from the items 106 if you remove the 40 mines.
7DS GSDEF so you can see some of what can be done with new templates for custom maps. It's not hard to figure out once you start getting the hang of it.
You want to modify a copy of it and put the modified "GSDef" of your own in it's own mod folder, but you could have Advent and Vasari militia, some advent/vasari bases, beefier occupied planet or less beefy , and have normal start give you a small frig/cruiser fleet with a couple of colony frigs and a capitalship -quickstart you could give players a bigger fleet than that and some defense/trade/refinery/etc...
Any Advent/Vasari militias you make must be put in manually via GalaxyForge, the game will only use the TEC defaults for the planets when you use the map maker.