Not a conflict per se, but you might want to move SCSII further down, simply because the reinstall can take (up to ten) minutes if you later decide to change any options. And you will, it takes a bit of experimentation to find the balance you like best. (I have SCSII second to last, but I'm not familiar with aTweaks or Dungeon-be-Gone - check their readme for compatibilities)

I would also add <span class="bold">TobEX</span>, because I think SCSII will install it anyway, but you want the newest version. It has some handy options you cannot get anywhere else, though some might be considered cheats or rule changes, so use your discretion. And TobEX should be installed in the very first position, before BG2 Fixpack. (Although this is an "in progress" mod that changes the EXE, it seems pretty stable, I've been using it without issue since day one)

I tried in the order specified (except that i did not instal Ascension after all) and noticed that aTweaks do not appear to work well with SCSII... no conflicts per se, but aTweaks undead appear to not be installed if SCSII is installed and aTweaks spell changes (it changes the Raise Dead and Spirit Hammer spells among others) are not applied either... i belive aTweaks detects that SCSII is already installed and simply did not install those components...

Dungeon-be-Gone works perfectly, SCSII appears to be all there too, do not know yet about the Unfinished Business and Banter Packs as i did not advanced on the play enough yet to verify if they are working or not...

if i have to choose between SCSII and aTweaks i think i´ll keep SCSII for the added challenge of play and the fact that it allows you to change the amount that Gaylean Bayle asks to help you (i changed it to 120,000)...

Also, i just figured how to transfer the whole game to a flash drive, so i can play it anywhere.... my next step will be checking GemRB to see if i can transfer the game to my android phone....

Edit: another problem found, apparently shapeshifting abilities from druids are not working now...