I must be very confused.
I'm using your mod. The Pollen and Perseverance use 1 admin, as advertised. But not much else is adding up.
For example, the Wraith says in the README it is Capital. EXP1_StaticShipBluePrintDefs.xml says it is Escort. The game says it is Support.
The Pewpewpewpew has the +100HP, but the game says Capital while the StaticShipBluePrintDefs says Assault. The README doesn't say anything.
In all cases, roles in the downloaded mod StaticShipBluePrintDefs seems to match the DLC's StaticShipBluePrintDefs coming from Stardock. Are these roles defined elsewhere? I put all 3 of your files in the same Mods directory. I have a 4th file, ImprovementDefs.xml, and that is clearly picking up, e.g. I set Computer Core to +20 research and the game clearly gives 20 research. Same directory.
I went a step further, and changed the Display Names of every single Mercenary ship--in every single EXP1_StaticShipBluePrintDefs.xml I could find (including the game install directory itself). Restarted a new game. The new names did not pick up.
You DID manage to get Mercenaries to change in the game??