For a withdraw-only feature, you could try deriving the Sapling Z-address & Transparent address from a Unified Address[UA] and prompt the user to choose where to withdraw the ZEC.
Support for Orchard Addresses in end-user wallets should roll out in the second half of this year.
Yes but you’re not really supposed to expose them like that, z_getnewaddress is technically deprecated but will still work to get a new sapling zaddy just like before but (I’ll have to check but I’m pretty sure why it is deprecated) not under the type: unified and so not apart of any ‘account #’ balance.