I had to Google for TCRT5000; this is what I found:
https://components101.com/sites/default ... asheet.pdf
It seems it can be used with 3v3 - it doesn't need 5v
Your Pi has only two 3v3 pins (1 & 17)), but you can use each to drive more than one thing.
So long as you don't try to take too much current, powering four or more TCRT5000 IR emitters from one pin is certainly possible.
Likewise, powering four or more TCRT5000 phototransistors isn't a problem.
And the LM393 each require at most 1mA.
If you're using a breadboard, paralleling multiple things from one point is so easy you won't notice you've done it. Otherwise, you'll have to get out your soldering iron.