Bitcoin multisig contract - to Lock coins with nTimeLock (BIP65) I really need help.
I am currently Developing a Bitcoin wallet and want to build in a SMS Based send function where the sender does not need to know the receiver publicKey. After the contract get executed on the reciever phone through the wallet the public key should be added to it and execute the redeem process / script.

Is that possible in any way?
No, it is not possible.

"Bitcoin contracts" are executing when spending funds from UTXO. If the receiver can do it without signing the transaction - everyone can do the same thing.