You only need one suit you're allowed up to three or four. The seravee counts as one suit. The systems AREN'T moot they're just not as effective. The F91's system burns the paint off the suit, Trans-AM is available on units who have units who are good enough to have the thing work on the gunpla. The last episode meijin vs. meijin proved that. Legend gundam is allowed and the funnels work just like anything else. Aila's custom quebley has a shit ton of funnels itself however for balance sake let's just say your character isn't very good with using them perhaps? I can't think of any real banes I can make the legend have. I mean in gunpla a jegan can take down a devil gundam.