Using SIGHASH_NONE in P2SH address
First, it should be said it's not possible to enforce which sighash flags may be used in a P2SH address. Signing is a concern for only the parties to wish to spend funds. Their intent can be captured using SIGHASH flags when signing. 

OP is right, and certainly can mix SIGHASH flags in an input script. Signatures in the same script are considered separately, meaning each specifies its own SIGHASH flags. This informs validating nodes how to verify the signature, and mixing them