If you have to ask for permission, then it isn't legal.
Hmm... interesting point. However, I might point out that before this faq, IIRC, Custodians were an FW only mini, with no official stats outside IA.
No, it would not cripple the SM. Because enemy ordnance would still have to go through the remaining THs and 6+ armor. SC already has 2 turrets. BB should get 4. Even if they would lose out on the ordnance war, so what? They're not supposed to win it anyway or even equal it.
And again, I do not know where you are getting your fluff reasoning. This is BFG, not 40k. If you want your supermen, stick with 40k. In BFG, SM are ordinary in most circumstances. SM handles the planetary assault. IN handles the fleet action.
I vote for 2. It has the most chance of the HA getting it approved.
@D'Art: Achem: as I said: read The Emperor's Finest for my fluff reasoning. In a nutshell, if you're going to do close air support and not leave your ship unprotected against enemy AC, you'll need at least two squadrons. Particularly since SC seem to often work alone. And in EF, it's made very plain that SC launch bays are much more efficient then regular IN lbs, (Caine notes that much of the usual detritus is missing, such as stacks of cargo pallets, and general care being taken to maintain the bay in a state of readiness.)
Second: Let me try this again, as you seem to have a serious disjoint here, GW does not, I repeat, DOES NOT, see these things a two separate entities, but rather a single IP. Anything the HA does has to be approved by them. I would prefer that we gave them fixes that might actually get passed. ATM, GW thinks Space Marines piss petrol and shit hundred pound notes, as they're the posterboys for their main line of minis. Regardless of balance issues (which this is also one of) this is a revision unlikely to get approved.
And, frankly, nearly halving an entire fleet's LB strength IS going to cause balance issues. This WILL make them easy meat for, at the very least, Tau and Chaos, and most likely Eldar and IN.
@Horizon: The admech LC, IIRC, isn't a Voss cruiser, though.