My strategy works well, but it requires two five stars and a Friend 5* unfortunately:
Altera (L90), Halloween Princess CE Vlad (L80, easily replaced by a L80-90 Herc if you're lucky enough to have one), Halloween Princess CE Waver (Support, L80-90), CE of choice, hopefully Halloween Princess for starting NP One Rider of choice (I was using Anne/Mary, L70) for backup if Vlad dies
The name of the game is to ARTS EVERYTHING.
First round: Go fast since Vlad is squishy, but focus on using Arts cards. If you're lucky, Waver should be nearly or actually ready to pop his NP when you're done.
Second round: Start off trying to build up Waver up to his NP and using his Skills to build the NP of your other beatstick Servants. His defense-up Skill pairs well with Vlad's own (pop that too) to give him amazing resilience for this second phase. Continue to pop NPs, leading with Waver's in hopes of Stunning the dragon; Altera's Photon Ray can add another Defense debuff to the dragon, and Vlad as a Berserker has a good single-target nuke. Continue to focus on Arts cards and the dragon should be dead in 3-4 turns (with Vlad around half HP).
Third Phase: Continue the exact same strategy as the dragon, only focus extensively on getting that 3-Arts chain to build NPs (particularly Waver's). Destroy the Pumpkin Knight as fast as possible (because Tamamo's hits are relatively weak, when the knight hits pretty hard comparatively, especially to Vlad without a Defense Up buff).
You should finish the entire battle by round 13 or 14 with Vlad possibly dying if you haven't Guts'd him at the right time or Tamamo decides she wants to make Uncle Vlad go home (at which point she instead gets bullied by a tiny rabbit pirate and her girlfriend).
It's painless, but it requires Waver as the linchpin of the entire strategy (since he is the go-to synergist for essentially EVERY team which exists at the moment on NA). Altera doesn't have an NP quite suited to this fight, but her ability to buff the team's NPs and its included Defense debuff WITH her huge amount of health and good Atk rating make her the team tank to absorb hits well for Waver and Vlad (and in a pinch generate Crit Stars with her third skill in hopes that they'll buff Arts cards for an extra NP gain attempt).