See what you're saying - but SISU themselves only use investors money, don't they? In essence then, this would mean burning one set of investors to the tune of £30m, so that the new investors get a clean slate. I'm not sure this entirely adds up, because I think the new investors might be wary of going the same way.
In truth, it's so opaque, that I wouldn't claim to see it clearly. I think it is clear that ARVO is part of SISU though - from the article below
http://joinmust.org/forum/archive/index.php/t-79099.html
Again, that to me points to SISU taking money off themselves if you simply move from Otium to ARVO as the new owners of the club and clear down the debt.
With regard to SISU buying ACL, I think it's hard to see that happening any time soon - they'd have to convince both the Council and the Higgs to sell and given that they're in a court battle at the moment with both of those parties it's hard to see that moving anytime soon. Never say never though...