Hey ill try to answer best as possible, going off whats been used on my submitted runs for indidiual level runs:

any gear, any character and stats are fair game and runners choice providing the character hasnt had any action replay or cheat engine/hex editor manipulation used on them.

Xtreme legends is classed as a seperate game so just classic game on this page (4th weps highest etc)

options wise do the runs on easy and also turn off the option which disables cutscenes mid missions (doesnt disable all cutscenes like freezing of river on yellow turban) as both of these will save you some time.

theres speculation on weather a generals hp is tied to your characters stat progression but people are still working out how this works.

some tips that may or may not help:

Death element damage always does 50% damage which scales to enemys current hp meaning when theyre full hp its worth using but if the enemies hp is around 1/5 its probably faster to just combo it down.

Theres a limit to how many models can be on screen at once which can sometimes cause generals not to spawn until trash mobs around them are killed, this is more prominent on the harder stages and moreso on splitscreen coop play, a way to mitigate this is to turn off bodyguards though on some levels i prefer to bring them as cannon fodder to draw aggro from enemy trash mobs (sidenote crossbow bodyguards do the most damage )

even when you max a generals stats on the character select screen the "true" value of the stat wont be maxed, the max attack one character can reach will be different to what another can reach this is true with all stats, on the equipment preperation screen the values shown for hp musou attack and defence show the "true " values meaning even with perfect attack items and max attack on the character select screen, a character like Xiao Qiao cannot reach a full "true" attack stat whereas a character like Lu Bu, Sun Jian or potentially Zhang Liao can gain more attack than her.

The games janky as hell and RNG on an enemy generals attack pattern can screw a run over hard but the games fun to run and i think the layout of being able to run individual levels really makes it accessable to jump into. Hodge right now is killing the runs on the board but theres still totally room for improvement as its starting to look like some levels are faster to run as certain characters ( due to start position or the level being easier for them in musou mode) .

Hopefully something in here was helpful any questions feel free im buzzing theres a few more people running the game now I just need to get back into it and try to steal a few top spot runs :P