I have a question on adding a lot of papershell crayfish and some Japanese snails to my pond this spring.

My pond is a little over one acre 15’ at shallow end 20’ at deep end. Rip rap medium size stone around whole pond and artificial structure in deeper areas.
It is a swimming and fishing pond,
Primarily a SM YP RES and WE pond with a good base of FHM and GSH. Has been stocked for two years now with good growth of fish, I hand feed twice a day during warm months.
I also put one gallon of aquashade in pond a year late spring.

Wanting to add the paper shells for forage and to help with pond cleaning and the Japanese snails for pond cleaning.
Would there be any downside to doing this? Is there anything I should watch for?

I see a little filament algae and a little water plantain growing in shallower beach area, also get some leaves blown into pond in fall.