I was confused when read your reply, but now i think i understand what you're talking about.
Your solution still falls on
type 3 if you didn't mention wallet which automate the process. Even so, it requires both Alice and Bob use same wallet, unless there's standard (such as BIP) where other wallet might adopt the standard.
- If Bob breaks the agreement and broadcasts or the transactions accidentally hit the chain then Alice will just withdraw bitcoins from their outputs.
This parts is similar with LN network where dishonest user attempt to broadcast earlier state of channel, which require honest user online 24/7 or use watchtower.
And AFAIK your idea suffer same problem.
It can be new wallet software with this functionality or an add-on to existing one.
As far as I know there are no existing wallet that supports to set an option of N days so, I am asking do you have a script or are you working in it to make it easier for the regular user?
I don't have anything implemented yet. One of the topic goals is to find out if that already exists somewhere. Don't want to reinvent the wheel ))
AFAIK there aren't any wallet which allow you make P2SH/P2WSH transaction.
I don't know of anything that exists with bitcoin script, but there's FinalMessage.io which is a custodial dead man switch, might want to check that one out
But then we're back to the older problem where higher degree of trust is required.