Personally, I think the Tremere would not have much of a chance of joining the Camarilla in this timeline.
In the original timeline, the Salubri was a weak and insignificant clan overall; they didn't embrace often due to their clan's views, and large parts of them were not interested in violence of any sort, which was what made the Tremere's coup so easy to pull off (along with the Tremere propaganda).
The Tzimisce are far more numerous, entrenched in heavily fortified positions (castles) and have a murderboner the size of Transylvania for anyone who'd dare to try taking their lands from them. Their Kolduns also have magical powers that can even the odds against the Tremere's thaumaturgy.
And unlike the Salubri, who were always viewed as being *too* goodhearted (and thus suspicious to most other vampires who are used to betrayal and deception), the Tzimisce didn't hide what they were. Yes, they were A-grade assholes, but they also slavishly followed a code of honor that even Salubri warriors respected (even if they didn't like it).
Upstart humans stealing the power of the Tzimisce would get the High Clans (and the Low Clans as well) much more agitated.
In fact, I don't see the Tremere joining any major sect at all... I think it more likely that the Tremere would end up as another independent clan, living on the fringes, offering magical favors to other vampires, and being hunted by just about any other vampire who found out their true nature.
Likely, only a few would survive until the discovery of the New World, after which the Tremere would probably flock to the Americas in order to set up a proper base in a new and foreign world, one where there *weren't* any major rivals or bloodthirsty and vengeful Tzimisce. After that, I can see their population booming, and they'd amass a much greater amount of power, enough to push them up from being a jumped-up bloodline and into being considered a clan, small and despised, but a clan nonetheless.