Imo the 2...e6 Anti-Sicilians are less unpleasant for Black than the 2...d6 ones, but that's my taste speaking. I don't get that many Antis in any case, but I do quite like the Moscow system for White and don't see how Black achieves 100% equality against it. Conversely stuff like 2...e6 3.b3, 3.g3 and 3.c3 seems minor in comparison.
In truth you could get Scheveningen style positions from the Taimanov by playing ...d6 at some point - I guess your liking of that comes down to whether you'd play the Najdorf with ...e5 or ...e6, given the choice. I don't think the Moscow is enough of a pest to not play 2...d6 (and White's other options like 3.c3 and 3.Bc4 aren't the least bit frightening) as well as 2...e6 in any case, if you have the time to learn two Sicilians.
If we extend the case to 2.Nc3, then 2...e6 is quite effective against the Antis as you have 3...d5 against 3.f4 or 3.g3. 2...a6 is also completely fine of course, but I'd be reasonably happy to play 3.f4 b5 4.Nf3 Bb7 5.d3 and 6.g4 even though it's not objectively better for White. Again a bit of flexibility is probably the way to go.
Finally, you may wish to consider the 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Qc7 move order to reach the Taimanov with 5.Nc3 e6 - the only real disadvantage I can see is that it allows the Rossolimo, which while totally respectable isn't as annoying as the Moscow in my view (3...e6 seems enterprisingly fine).
It really is down to a matter of taste in the end - the difference between 0.02 and 0.12 is nothing compared to how much you like and understand the positions you get. On a random note, the most Flexible Sicilian would surely be to play all of them.