Thanks @nc50lc for your message and assistance.
Passphrase solution
At the point of writing this I have to assume I can not trust myself and will try all proposed solutions. Will it affect my wallet if I try to restore "another" wallet with a passphrase?
Not at all, your wallet is just a collection of private keys to move your coins which are stored in the blockchain.
With a passphrase (
actually "BIP39 passphrase"), it will just generate a wallet with entirely different set of private keys, the balance of the wallet without a passphrase/different passphrase wont be affected.
If you want to restore the wallet with "
0.000X BTC" balance, you can just restore the seed without the passphrase.
Assuming that the device where it's restored is secured, there wouldn't be any major circumstances on trying to restore it with a passphrase.
Regarding sending to same wallet, will the keys be different types in iOS / Android and make me have to search for other keys/account types?
Developers do not usually do that, most of the time, there's always cross-platform compatibility.
I'm also pretty sure Mycelium haven't changed derivation path in the earlier versions.