this doesn't sound like a "wallet" to be honest so maybe it is best not to call it that and come up with a better descriptive name instead. and if it is truly a "wallet" you want to focus on then the 4 features you have listed here are not the appropriate ones to consider for a "wallet".

the main features i would be looking for in a wallet supporting multiple cryptocurrency are:
- the option to run it offline as a cold storage and be able to sign transactions and broadcast them on another machine online.
- the wallet has to be peer to peer instead of relying on a centralized server to get the transaction history, blockchain data,...
- of course security is obvious.


again we come back to the initial thing i said about "wallets". i personally consider this to be both a security and a privacy flaw in a "wallet" software. and it will probably open up attack surface.