Assassin questions. A LOT of them.

Here's a question. Do Avenger + TT have the same damage formula as L7?

no

avenger is affected by mastery.

but lucky7/TT follow their own formulas.

Will Dexless be better then Low Dex/ Normal DEX. For the same amount of funding, i would say dexless would be stronger early on, but Low/DEX will win towards the end, unless you are truly poor, in which case its kinda hard to be damage whore. But As time goes on, dexless may win out, depending on what is released. If the release shoe luk, helm luk scrolls and a level 100-110 dexless claw, dexless may still be stronger for same funding at level 16x lol. But with Dexless you lose out on 13-17 dex on helm base, and there are no helm luk so there is that, plus on average top/bottom is gonna give you more stats then overall., for a better cost. Plus when you get down to it, any skanda over like 54 atk is going to cost more then 60 atk craven(its an estimate).
You figure initial 25dex plus 15 from helm is 40, and getting an extra 15(making 30 dex helm) on helm isnt THAT hard now, so 55, plus 22 if you can afford pendant and egg, thats 77, decent bottoms are like 14dex, so thats 91, 12 dex earrings arent too hard to come by, so you up to 103, pair of 5 dex FS, and you are at 108. Then you though in nose, cause you mentioned you can afford one, and thats another 3-5ish for avg, so thats 113. You have 27 more to dex to get with Eye Acc, cape, and some ap put, or you could just use sauna instead of top/bottom. W/e. lets say you keep luk cape, no Eye ACC, and you use top/bottom, 27 points into dex and 60 atk claw > 27 points into luk and more expensive 54 atk claw.