Thanks,
So the SRAM is completely wireless? Im guessing you are saying I would have the blips only and standard TT hydraulic brake levers?.
Correct. Use any brake levers you want, you don't necessarily need the SRAM ones - mechanical can save some money given that braking power generally isn't a high priority on a TT bike.
The L-Twoo TT stuff is not widely available yet (that I've seen), and based on their other products so far I wouldn't say it's reliable enough that I'd use it if I was travelling for races (and also consider you won't be able to get spares in a hurry - say you get to your destination and find something isn't working, or you forgot your charger).
Shimano TT electronic is still wired - not worth bothering with given the SRAM parts are cheap and easy to find.
Shimano mechanical not a bad option if you're doing it on the cheap - you just need the bar end levers. Still, you have to go through the pain of the cable routing.
If you're okay with 1x then I'd say SRAM electronic is the best budget TT option.