About Katana's range attack and stability

Do some katanas have different range attack (1-4m)?
Do STR and DEX affect stability of KTN?
Extra Question: based on description, 2-handed skill grants Critical damage increases but when I saw coryn website, it describes that skill increases crit rate based on lv but it doesn't mention crit damage value?

 

as far as i know, they are 2m. but some other weapons have varying attack range, so it's not impossible.

it doesn't increase the critical damage stat. during damage calculation, it multiplies the total atk by 1,5 if a critical hit occurs.

 

Afaik, most ktn have auto attack range of 2m. The only two exceptions atm are Scarlet Sakura Fairy Sword and Black Shadow Nodachi, both having 3m aa range. They have 60% stability (10% less than the average 70% of most ktn) in exchange, though.

Yes.
For more information, check the guide section in Coryn website.

Ingame description is usually very vague and misleading thanks to astupidmo translation. The actual property of the skill is that for ktn, when you deal a critical hit, it increases your ATK by a specific percentage for base damage calculation.
Example: your ktn char has 1k atk and lv10 Two-handed (which has crit atk modifier bonus of 50%). When you deal a normal hit, it uses that 1k atk for base damage calculation; but when you deal a critical hit, it will use 1.5k atk for base damage calculation.