All units in any X-Com game, except for the invisible and semi-invisible units, are vertical cylinders. The diameter of a cylinder is determined by the LOFTemps used, while its height is determined in the ruleset. It's just as simple.
What wasn't/isn't clear to a layman like me is just how often it actually happens that a shot deviates so little that the lofTemps and height settings make a difference. Most misses are way off, after all, and the cases where it kinda looks like the shot should've hit but didn't, i.e. when the size of the cylinder might matter, are quite rare.
None to negligible. Below 5 tiles, it can be raised to 'very little'.
Also their invisibility hack is not to make them immortal, don't be ridiculous It's to give them a bit more chance to cut you down with a katana if you're careless. Star Gods can be exploded as well, they're medium-toughness enemies. Again their invisibility is for attack, not for defence.
Also melee works just fine on both these units, unless some glitch happens that is
But I guess this answers that.
To be honest, my biggest gripe with this lofTemps thing is that it simply feels stupid and/or unfair, or something like that at least, not that it poses a problem that is impossible to work around. Again, these are things that are easy to change if one so wishes, so I suppose what I'm mostly doing here is merely bitching and voicing my annoyance, not a demand for official fix/change/whatever.
I can appreciate the intent behind these stealthy/difficult to spot/hit units, but the way it has to be done leaves a lot to be desired.