My first question: what is the best type of board to get for soldering upon? (I have one of those white bricks that easily pit and crumble now - ick)
Nothing wrong with those.
SInce you’re working in a condo, you need multiple layers of heat
protection. I have a kiln shelf that looks to be made out of the
same stuff as a pizza stone and a magnesia block on top of that.
You could buy Solderite pads for one of your layers.
Charcoal blocks are also nice.
Just protect your place, use more than one layer. It’s all fine, it
doesn’t really matter.
Charcoal reflects more heat back onto your piece, which is either
good or bad, depending on what you’re doing.