This new idea... The whole attack/escape/rescue plot is a book length monster all on its own. I've read more than a few books with that plot (end up alone or in a small group of survivors, fight nature/enemies/time to get to a position where rescue might be able to happen) though mostly in older sci-fi.

I could see this idea being at least a trilogy if you want it to be. The attack,escape, and formation of the core pack in book one. Then book two would be political shenanigans and obtaining a ship, or several, and volunteer (or not so volunteer) settlers. Depending how much the "normals" know it might be possible for the Hounds to arrange things so they get shipped off as a punishment or some sort, getting the government to foot the bill for the ships and supplies (though that could leave them open to substandard supplies). Maybe they actually had an uprising. The spin could run two ways easily, "we're being compassionate and giving them a whole world so they don't have to be on reservations" and "only seven people out of X hundred survived that planet, if we ship them there it will take care of our problems for us". Book three would then be the actual settlement of the planet and figuring out how to survive as permanent residents. If they managed to get shipped there by the government it could also included figuring out how badly they got fucked over on the supply side of things and surviving anyway.