I think Brampton will be brought in for this year under a merger. My guess is the give the ECHL a go for a season (I foresee 3 at the most) before the close up shop.
The question is if MLSE would want to affiliate with a shaky team only to have to find a new affiliate in a year or two when they are affiliated with a much more stable franchise in Orlando. And even though there are double affiliations in the ECHL Tampa has an affiliation with the Beast. Would they swap? maybe
That could be the only decision factor in any affiliation with the Leafs for Brampton is that any Leafs prospects placed there only have to go from Brampton to the Marlies across the GTA. But Brampton is also closer to Syracuse than Orlando for any Lightning prospects, However I'd say the Lightning would gladly take Orlando under their umbrella.
Also Brampton has a little better chance in the ECHL as they aren't as isolated, plus they fit in the Atlantic division with Wheeling, Elmira, Reading and whoever is in that division I think the Cyclones now.