no shisui stats dont increase for BT apart from the stat increase when you 4* him . also as to why minato kills you so fast . it could be irromvable buffs that are responsible or non-round based buffs . madara etr wont remove non-round based buffs i think . also it could be the work of an assist ninja . also remember minato BT is 4* so more power .

Tenten and Danzo are already good enough . But you c*so try to use Torune Aburame to do more damage against immune ninjas like minato and kushina .