Reddit reviews 2XU Men's Active Tri Singlet

Generally people wear a tri-suit, or a pair of tri-shorts and a racing top. Here is an example of some tri-shorts. They have a bit of padding for the bike, but not a lot and dry quickly and fit under a wetsuit. You could also look at a tri-suit like this one that has the same stuff as tri-shorts and a top, but it's all one piece.

As far as your bike, you can ride on anything, but you can definitely put bolt on aero bars on your bike. To get the actual aero position however, you will probably have to move around your saddle and maybe get another bike fitting to adjust all the things that need adjusting. You could also just ride without the aero bars, you wouldn't be alone