I see, thanks.
So even if the change address does not show up in the Electrum wallet for whatever reason, it could eventually be found/generated deterministically by increasing the gap limit?
Yes it can be found deterministically but not by increasing the gap limit. The gap limit that you can set only affects addresses in the main wallet. The gap limit for change addresses is fixed at 3. So you just run that create_new_address(1) command to generate new change addresses.
But yeah the point is that the seed and a copy of the electrum is all you really need.