I would modify it slightly with a good balance of Life Tap and Sustenance. Sustenance is mainly to top you off during downtime combat and after that kill skill time runs out from Life Tap. I heard flicker helps with Scorn’s chance to slag but I am not sure if that is confirmed. The rest of your build looks pretty solid.
As for guns the most obvious choice is the Bekah, but the question is what do you want for the other three. I have seen players complete the peak with Bekah only due to its absurd ammo efficiently.
Twister is great for a shotgun, you can try the Orphan Maker too when the enemy is more mobile. Striker also works fine here.
It is hard to recommend anything better than the Maggie, a Jakobs Iron perhaps but Maggie is just better if you land all pellets.
Sniper is a weird one, Cobra if you have the Bee I guess, but if you are using the Bee, just use the Bekah so that’s that.
Honestly I don’t use Jakob snipers much at the peak with Maya, I am not sure why.
Jakobs Relic with more Mag Size and Recovery Reduction.
To me the Jakobs Maya peak is simple, and it revolves around the Bekah, if the enemy is inside its split distance = use a Jakobs shotgun, otherwise just use Beekah…without any ammo issues and worries.
Oh and don’t use a Rough Rider. Jakobs guns alone is sufficient for this challenge