House built 1880 Upstate New York

Issue- hydrostatic pressure water infiltration, basement always damp limits use and has mold and mildew.

Proposed resolution drain tile at base, waterproof coat foundation.

I have dug up a portion of foundation (Purple sandstone and gray limestone) to footer 5 1/2' deep to expose stone and some mortar is loose and missing (20-25%) shallow voids nothing seems to go all the way through and stones seem solid.

I am trying to find a product I can use to repoint without damaging existing mortar or stone. I have been told products readily available at box store are too hard and may cause mortar failure or cracking or splitting of stone.

Non-hydraulic lime...or... Lime putty...or...High Calcium hydrated lime mixed with 2.5 parts coarse sand

I can not find and local suppliers are clueless.

Also what will be safe to waterproof wall assuming use of lime mortar.