Racial Heights in Middle Earth.

Men, elves, dwarves, and halflings seem about right to me. I've heard some describe ME elves as 7+ ft tall but I think that's excessive, or at least at the very top end of the range. Perhaps some elf lords grow taller as the millennia pass, or maybe the eldar are a bit taller than noldor or sindar.

Numenoreans I never thought much about, in terms of height; I'd make them between man and elf in height, but closer to elf. I think both elves will be physically strong, not thin and frail as they are often portrayed, and numenoreans likewise. Numenoreans should be slightly inferior to elves in capabilities, but greater than men.

Goblins and orcs are two names for the same creature, and I do not differentiate between them. Doing so feels like a D&D-ism to me. Since they are corrupted elves I don't think they should be too short, but since they are likely degenerate then probably not as tall as elves. Your point about hobbits impersonating them is well taken though. I imagine goblins have significant variation in height, much as humans do, and that could be regional. Maybe there are pygmy orcs beyond the Harad, and they could occasionally suffer from dwarfism. Also they are described as running "stooped over" in their tunnels, and perhaps they slouch or stoop on the surface too. I think I'd place goblins and orcs between 5-6 ft on average, same as men.

Uruk Hai seem about right. I use "hobgoblin" as a synonym for these, goblin and hobgoblin being mannish(?) names and Orc/Uruk being elvish.

I could go larger on trolls, up to 10-12 ft, but think there would be lots of variation.

I never thought too much about entish height. I suppose I pictured them around 10', but I like your suggestion better. They are "giants" after all, and trees as well.

I have made a slight edit noting that "goblin" refers to The Hobbit and "orc" refers to LOTR.