Am I able to use the Upgradeable Proxy pattern from OpenZeppelin on Kaleido or are there any restrictions?
Yes, you are able to use the proxy pattern with Kaleido and there shouldn't be any restrictions. This readme should be a solid guide on how to set this up with our contract management system - it also lays out how to update the ABI and point to it in our system as per your third question.
In a future platform release, Kaleido will be incorporating the proxy upgrade model into our smart contract management capabilities. This will further simplify the process and only require a platform user to inject the proxy with the upgraded contract's new address.