The Pro80's are easy enough to drive that they get enough volume from my LG G3 and G5 (stock headphone output).
Tbh I only use the Pro80 among the three because I find it to be the best ones among them and I've got too much other stuff competing about listening time.
Same goes for amplifiers, I typically uses whatever I'm reviewing at the moment or the Burson Conductor V2+ (overkill of course but that's what I've got permanently in my main system).
The TS662 I wouldn't recommend to anyone. I find them to sound hollow, closed in and overall unnatural.
The HI2050 is very similar to the Pro80 but with sharper treble, looser bass and maybe an ever so slightly larger soundstage.
The Pro80 on the other hand I totally love. I'm on my second pair now, the first ones literally failed a part after years of heavy usage (I've got four kids still living at home) and I just couldn't live without them so I got another pair despite having over a hundred headphones and IEM's at that time, nuff said