Hit rate is linear function of hit: hit rate % = (hit / ((your level – 1) * 50 + 400)) + addition hit rate %
Dodge rate is diminishing return function of dodge: dodge rate % = (dodge / ((your level – 1) * 50 + 400 + dodge * 0.7)) + additional dodge rate %
Parry rate is diminishing return function of parry: parry rate % = (parry / ((your level – 1) * 36.5 + 224.5 + parry * 0.5)) + additional parry rate %
Hit rate is then subtracted from targets dodge/parry rate when doing damage calculation. Players have a starting base 10% dodge rate. Critical hits cannot be dodged or parried.
1) In PVE it’s hard to get solid information because the stats of monsters are hidden. The advice on CN is ~10% hit rate for DPS classes but that’s mainly because other players start with a default 10% dodge rate and most people’s builds are geared for both PVE and PVP.
2) In terms of positioning, where you stand does not improve your accuracy in anyway.
3) I’m gonna guess that you should use the targets level for your hit rate calculation and aim for 10% with that. ie. 10% hit rate is 280 hit against 49 targets but 310 hit against 55 targets. Can’t confirm though.
5) What ever your target’s dodge rate is.
There’s other factors that go into whether or not your skill will land. Leaving your normal skills or special skills low level will cause their damage to miss more often and their additional effects will be resisted. Some skills also have hidden modifiers increasing the chance they hit/miss.
To sum it up, you probably aren’t going to find solid answers to your questions regarding PVE mechanics because hit is an after thought. If you roll your earring’s veneration’s to hit, get high crit like you’re supposed to and keep a balanced and decently leveled god grid you can pretty much ignore any theorycrafting about hit mechanics.