Sounds good - great.
I would suggest the 2nd option, to "
As for other option - that's also would be a solution that when you meet Negan, you would have list with girls who meet requirements BUT first option (adding them as companions) gives other options in the future.
For example while you travel, slaves might try to escape, etc."
Because I suspect it will be much easier for you to code, you could also make a 'function' for this type of exchange, which of course you can use in future in game, as well as modify quickly for other such "shop/exchange" scenarios for quests, etc quickly.
However slaves as companions (without guest requirement first of course) might be good too. Why? Well of course you would have to invest time in training them, their submission and strength - a lot of work, but by default have some risk of loss of them escaping, being eliminated in someway factored in...
In other games for example: slaves are just that disposable slave workers, used for that. In this A.W. slaves can be used captive in garden or in cells. However thrust on the street they can be killed or without proper management driven to depression, suicide (some more/less based on characterists (maybe masochists, highly submissive less so for example)). Similarly a slave companion balances this equation. So you already have these features, mechanic in game to great effect. The slave companion now-or-later, will only be an additional feature of game, logical, inline. The Negan quest is obviously a simple quest, so likewise can be fixed easily to just transfer slaves too.
It really then depends on you as developer, if you wish to introduce and develop slave as companion option or not at the moment.
But either way as the temporary quest solution or slave companion - either works. The temporary question solution may be of value alone too to create modular functions as I mentioned for reuse. And you could always introduce slaves as companions later, mull over/design the item and introduce at any time per need.
Great news. Thanks. I will say that you are a developer that actually tends to the forum is responsive and cares to develop game and listen to people - that says a lot, and personally I am glad to follow this game and its progress. I was worried for a moment, but will be patient.