Just post some very useful questions in this thread, i'm very sorry if they are asked before but i didnt find them the first one will be I allways wondered, do buffs count as magic, and if they do, egyptian and viking damage buffs are boostable by upping your magic power?
The buff's effects listed in their description when you mouse over them are static, but the bonus effects, such as the occasional lightning that Power of Magic Steel gives, scale with magic power. A great resource to check these effects is Dredmorpedia.
Do Modpacks that add multiple rooms, such as Faxpax, Interior Dredmorating and Roguish Renovation come complete with additional variations of Brax Shops? I seem to encounter somewhat/slightly less Brax Shops with those mods turned on.
I am not really the authority on mods (I've not used any since I started playing); you're probably better off asking on the modding general. It's been a few months since I've played, but a quick check of a few floors from an old run that won suggests that every floor is guaranteed 3 shops.
I've seen plenty of Floors in Normal Dredmor(Vanilla, without NTTG) that have only one shop. Usually happens within the First 4-6 Floors(especially floors 3 and 4). But almost every other floor has 3 shops in Vanilla without NTTG.
I should have mentioned I never played NTTG, but then again i did say it's been a while since i played. I was initially gonna say 1-3 shops per floor past floor 1, but i thought "might as well check", and managed to find three floors in a row with three shops. So I sounded dumb by luck of the draw