hi, we think we're on same both, i have a 4 and 18 months..and the 18 months old understands and knows HOT...
I had a BAT tube amp and pre amp...but have since unloaded the pre-amp. and the amp were in boxes until recently...and are now on the market..
(side note: they do make a tube cage for the bat vk75se, contact victor for detail, this was share with me by a gon member here, john)
as for the Yba passion..i had opportunity to purchase it, however, imho...the pre takes a back seat to the amp. and if coming from bat...well, i think it may disappoint...
also, like you, i am downgrading..but i rather call it downsizing...one: due to space consideration, two: the tubes and toddlers just don't mix, and three: wife has decide junior is to take piano lesson and thus we are now in market for a piano...and my HT/listening room/living room will house the grand piano....
to answer your question, most logical would be the bat integrated...