I see them as possibly being a special type of stage hazard. Both come from space, and they could actually show up only in those types of stages. Sakurai didn't confirm their role, so it's nothing but speculation for now. There is no confirmation, regardless of "deductive reasoning", since that doesn't confirm jack. Theories are not facts for any wiki, which is what I'm talking about, the purpose of adding factual content to a wiki, not solely speculation.
I'm going to have to disagree with you here. Are you seriously considering Andross to be a stage hazard on Mario Galaxy? Really?
In this case, it IS a matter of deduction. Characters can be playable, Assist Trophies or stage hazards. Stage hazards are related to the series the stage comes from.
So, Andross isn't a playable character, as he doesn't have a page on the website. The stage shown is Mario Galaxy, a stage from the Mario series, while Andross is from the Star Fox series. Finally, Andross is an Assist Trophy in Brawl. Long story short, he's not playable, not a stage hazard and is an Assist in Brawl. What is the logical conclusion you can draw from all of this?
Seriously, why the hell would Andross be a stage hazard on Mario Galaxy? That's insane logic and you know it. Just because Sakurai doesn't explicitly tells something, it doesn't mean you can't use logic to deduct what's going on in a picture.
Now, if Andross was shown on a SNES Star Fox inspired stage and there was no mention of it being an Assist Trophy, then you could logically assume that it could be a stage hazard, but even so, the picture would be unclear on whether Andross was a stage hazard or an Assist Trophy. Something familiar here?
Should be, as this is the exact same situation as the Dark Lord and the Find Mii stage. The Dark Lord could be an AT or a stage hazard, as both possibilities are valid considering the picture's content. Of course, Famitsu has stated that the Dark Lord is an Assist Trophy, so this is no longer an issue, unless the information happens to be wrong, something I doubt considering Famitsu's reputation.