I’d like to create a 2 of 3 multisig bitcoin wallet and I’m thinking of storing one of the private keys on a hardware wallet like the Ledger Nano S, a second on a paper wallet, and a third on a software wallet that allows multisig accounts such as Copay or Armory.
My question is, if say in 5 or 10 years, Copay or Armory are no longer around, can I still restore my multisig wallet? Can I just restore it to another software wallet that supports multisig? Creating and restoring single private keys from seed phrases makes sense to me, but I haven’t seen anything about restoring multisig wallets.
I’m not actually sure if I can answer your question as at the moment I don’t use a multisig wallet. However, the seed / private that you get when you open a wallet is usually compatible with several wallets. So even if one wallet goes out of business you can still import that seed to another wallet.
Also, as far as I know a multisig wallet doesn’t mean that the key is stored on different wallets. The keys are all stored on the same type of wallet (e.g. Copay). So you can’t spread them around like you asked in your question.
I do however strongly suggest that you do some sort of experiment first before sending any substantial amount to a wallet by recovering its seed / and seeing that the process actually works.