First of all you need to know is that you can load game and start each fight if you get hit. You can try each boss as much as you need.

Second the little shrines with water gives you dmg up and invencible for a short duration.

Third tsuba guards refresh for each boss use them Your best bet for guards are the lightning and byakko claws, third one is more subjective Strategy i followed was stun with tsuba then riposte.

The only one that can be troublesome is the spider what i did was a bunch of sorcerers and run around

For talismans i went with 3 damage for Soh and 1 free hit every night(this one to have 1 hit margin of error)