but you are certainly able to spend the UTXOs using coin control
It depends, how it will be locked. Because you have three options:
1) transaction locktime field
2) OP_CHECKLOCKTIMEVERIFY
3) OP_CHECKSEQUENCEVERIFY
And then, it is possible to put a lock on the output, instead of putting it on the transaction.
You will need too many transactions if you pay yourself daily.
It depends. Because it is possible to write double spends. So, it is possible to make it more flexible, if you would have one transaction, sending you some coins today, and another transaction, sending twice as much tomorrow, but using the same inputs. Then, if you don't need those coins, you can wait, and save on transaction fees.
But yes, predicting all scenarios require creating a lot of transactions. Unless there will be SIGHASH_ANYPREVOUT, or unless you use tricks like Homomorphic Encryption.