I think the idea is that they would want to lock the coins in place before any fork happens. Your plan seems like it requires the fork to have already happened.
This is not possible without a replay protection, which BU refuses to include
It is possible to lock your coins in escrow before the fork. It isn't possible to do an atomic swap between the Bitcoin chain and an altcoin chain that doesn't exist yet.
From what I understand this wouldn't double his stash, lol.
After that happens Loaded offered him to trade up to 130k Unlimited BTC for Core BTC. So Roger would have double the amount of Unlimited BTC and Loaded would have double the amount of Core BTC.
I think the point was that adding 130k to Roger's stash wouldn't double it. In the same was that adding 130 to 400 doesn't double it.
Nobody really knows how many coins Roger has left, but there are rumors that it's around half a million.