So I don't know about naming the chapter and all that. But considering this is Solar Auxilia which are more or less Imperial Guard Veteran level equipment at a minimum I think with integrated aerial and naval forces to move them around and support them?
Yeah, they are absolutely going pirate. More importantly, they're going pirates that are closer to nomad hordes than pirates, coming in to a region, raiding it whilst major forces are devoted towards conquering high value targets and then pulling all the forces back up off the high value targets along with their loot and moving to the next region once the threat level becomes too high. So here's my thoughts for their training and equipment:
[X] Surprise Head Hunters
-[X] Deepstrikes: More so than even other Space Marines this chapter has gained a mastery of the orbital strikes Adeptus Asartes are famous for.
-[X] Extra Assault Packs: The Chapter has enough Assault Packs to equip extra Assault Marines.
-[X] Extra Thunderhawks: The Chapter has access to additional Thunderhawks.
What this is, is absolutely about taking out the greatest danger of the Traitor Solar Auxilia (the fact they still have a lot of their old discipline and chain of command making various groups cooperate more easily) to allow clean up of the leaderless forces to be easier whilst also making it likely that any escapees will probably splinter apart so the larger armadas are less of a threat making it so smaller task forces can be used to cover larger ground. Even after the Traitor Solar Auxilia are cleaned up or escaped to an untouchable safe haven, this will still be very useful for both high leadership forces (such as Orks via dropping a strike team on the Warboss) and dealing with pirate groups.
After all, it's all about fast deep strikes by high mobility groups, along with solid naval warfare thanks to the already locked in traits. Which more or less means the strategy is to disable naval assets or drive them off then immediately drop several Assault Marine squads on important targets or enemy concentrations which can not escape the Assault Marines long enough to go to ground.
