While the minotaurs only get a page, and nothing about a lot of Terminator Armor, they come off as right jerks. Hate for any non-Deathwatch or Minotaur Astartes. Honestly, not even good PC options IMHO. Does mention they are willing to go after other chapters though… then again, the Crimson Fists are said to have taken part in two Chapter Attacks. So hardly original. (Stupid High Lords seem to have forgotten the bloody point of the Space Wolves!)
The Red Scorpions? I think your issue a bit moot after this. It isn't so much they were lost in the Warp as they were cut off, and found a homeworld that they started to recruit from and could thus hold off. Especially with their extra effort to hold off bad 'stuff' in their gene seed. Like… any impurities is a death sentence style thing.
And it says the 'lost contact for centuries' thing isn't even that uncommon for Marine Chapters. It DOES happen. Especially with Crusading Chapters. the Marines Errant are often above 1000 marines simply because a company is missing for decades or centuries. They finish replacing only for the original to finally turn back up.