Yeah, Diverhank nailed it - two very different lenses. Important to note that the 50mm 1.4 is NOT a macro lens and that was something you mentioned in your initial post. I used the 50mm on my T2i and absolutely loved it, though I eventually upgraded (and much preferred) the Sigma 30mm 1.4 for the "normal" focal length on the crop-sensor. I now shoot a full frame and primarily use the 50mm but will likely get the 100mm shortly. Be sure to take a look at the Sigma 30mm before buying the 50mm Canon but if Macro is what you're looking for, you can't go wrong with the 100mm L.
I would recommend carbon fiber, which is expensive but probably worth it. Also, get something with a heavy duty lock system. My cheep manfrotto tripod has something where you shove a button down to hold the camera in place, but sometimes it slides around. Also, this tripod has a quick release system where you attach something to the camera so it can easily be slipped on and off the tripod, but this makes it a bit wobbly too. so, i think that you should invest in a heavy duty carbon fiber tripod, especially with the macro lens you got if you want to get as much out of a tripod as you can. I wish I had.
I neither own, nor have I used the Sigma 150mm, and as such it would be irresponsible of me to offer an opinion. On the other hand I can state that the Canon 100mm f/2.8 IS II is, in my opinion, a superb lens. It's so much more than just a "macro" lens.
Yes it is. Since your T5i is Crop sensor camera it's going to be like you have 160mm lens on Full frame camera. I hope you are aware of that situation with crop sensors. I'm using it on Canon 60D and it works great!
You mean autofocus doesn't move smoothly, can't autofocus easily and go back and forth or it does not even try to autofocus? Mine (On EOS 40D) does autofocus, it searches from close to farthest smoothly but it does not always autofocus easily, though I think the last one is due to lack of contrast or inability of the body rather than an error in the lens itself.
Yes. Since 1987, the EF lense mount has been the standard mount for canon DSLRs. The 70D has a EF/EF-S mount. The EF-S mount is reserved for only non full-frame camera bodies in Canons lineup. If you attached the 100mm 2.8L to a 70D, the equivalent focal length would be 160 instead of the standard 100 because of the 1.6 crop factor of the 70Ds smaller sensor size on the non full-frame camera body.