1. I have a good experience with decapitate since its basically filler power attack when your flurry is down. It's also helps against metal armor dudes. Not 1-shot situation, Ofc. But it could if decap crit.
2. It's actually worth it for additional layer of RNG. 35% isn't that bad in practice. I find that high melee resistance is harder to get for light armored build, since even dual low energy emitter shield still sucks against some knifer / stalkers, while evasion are good enough investment since it protects against ranged and explosive. Dual high shield emitter is also enough to handle AR and below, and able to protect you from off-screen sniper, if not completely evade it
3. This one doesn't really matter much. Higher INT does removed few skill points, which can be used to other things, but the "other things" are very optional imo. Persuasion, trap, pickpocketing, stealth. Bit more agi boost makes your evasion a little bit higher and you could helps bypass some agi check on certain places without going full meta.
4. This is build decision. Balaclava are easy to craft and you'll want rathound regalia for swag and +1 str, it also have good stealth amount. Going all-in just for tabi is huge waste of skill points, which usually means you have mediocre evasion, which ain't even worth to have thanks to weird mechanics that Styg felt still fair to the player. And in a way, max STR sword doesn't really need crit chance, because the base damage itself is already huge. Max DEX sword would want all the crit chance they could have, tho, since high DEX means higher crit chance it's possible to get 95% chance or something that ridiculous.
I honestly don't want to test DOM myself. It's a chore and not fun for me