I took another look at the GM's plot snippet. It sounds like the perfect excuse for a Lance of mechanicum aligned Knights to be deployed.

Plus I think overall a better story might be had if we were all the same house. Yes being from different houses is fun for character creation and feeling like a snowflake. But I think I there is alot of story potential and interaction that can even be improved if we were all from the same house.

Plus again, it just makes sense thematically. Especially if we are liberating a forgeworld of all places.