Hello there again, here I will discuss the third problem, called out in the first post, the skill checks:
First of all to clarify what skill checks are: These are some basic conditions for you to master while using something.
For example the major skill check of ranged weapons like pistols, is aim.
Some weapons make it easier for you to pass a certain skill check, like shotguns, but give you other skill checks to manage like shorter effective range. Other weapons lean into this skill check and require you to master it fully, by making it harder but rewarding you for it, like snipers, giving you an increased amount of damage.
Now typically aim isn't the main skill check of melee weapons because you deal area damage most of the time, so I think it would be possible to just copy the most common skill check of melee weapons into FFW- combos.
I think, if the melee weapons make it into the game, there should be a few combos that all the weapons share like LC-LC-RC
(Left Click-LC, Right Click-RC)
But also there should be weapon specific combos like for a long sword:
RC-LC+Jump-LC
to dash forward, throw a few enemies into the air, going up with them simultaneously and then plummeting down, crushing all enemies beneath you and throwing the ones you attacked previously to the ground.
Of course I think this should deal immense damage like the whole combo about 200-300 DMG, but to not make it overpowered, you could add a little cool down like one second so it seems small but in combat really restrains you. (I am not a professional game designer so please don't flame me if I get the balancing wrong)
Just as in the previous posts I encourage you to make suggestions and add new ideas to this.
Thank you for reading and have a nice day!