^^ Just to stretch the paradox, what if this "forever" existed only in the dream, and only within the 45 minutes or so of the physical reailty REM cycle?

Why not? We're completely bypassing reality here, and this agrees with the OP anyway, so maybe the point of view that if "infinite" time dilation is possible in a LD, it can certainly all be done within one REM period!

... might as well go all the way with this!