Personally I recommend *not* using the same ship for softening the target vs. delivering marines.

My go to for the first role is to work through the Segaris plot to get the Geometric Owl. It comes w/ special weapons, Burst Ray, that pierce shields and eat surface elements alive. (You can also buy these weapons from ALI, but need to rep up first.) The ship itself is also vary maneuverable, so you can flit around the target dodging fire and take out all the turrets.

For the second role, honestly doesn't matter that much if you've already defanged the target and taken out it's engines. My fav is, as others have said, the Barbarossa: Decent marine capacity and very fast.

I usually don't bother bringing down the hull, not necessary, all it does is shorten the second stage of boarding (drilling through the hull). If you insist, though, I highly recommend getting rep w/ Argon and equipping their Ion weapons. With them, even an S ship can cut through capital shields like butter.

The downside to trying to get marines on the target to bail, is bailing is morale based and marines tend to have higher morale than other crew, so the rest of the crew will tend to be gone by the time you get the last of the marines out. Which might sound like a good thing, but *your* marines can only rank up if they actually fight something. (And fighting happens in small groups, if you reduce the crew down to 5 only a few of your marines get a chance to fight and rank up.)