Ignoring the subs (which in the end may be necessary with all three) the Gallos are $2K for a pair and KEFs $1.5, so not widely divergent.
The quirkiness is the space goes (r to l) stairs down, recessed built in cabinet (likely where equipment will go and possible right channel on top), about 10" of wall, fireplace, about 10" of wall, stairs up, about 10" of wall.
And you're right the KEFs have two foam sizes for experimenting.