You can get them from baldurdash (
http://members.rogers./com/mrkevvy ), under the SoA tweaks section. Theres a warning in there to the effect that those tweaks dont work under SoA. It should really read that some of them dont. The merchants, among others, work perfectly.
If you decide to use any others though, take note of what files they override so you can take them off if needs be.
It shoudnt really matter when you install them, neither TDD nor TOB overwrite those areas AFAIK. Well, ToB does but only because it includes one of the merchants anyway. For safeties sake though, you should probably get the official stuff running first.