No. Please don't add anything that will cause the game to take additional time to release.
Even when it comes to these particular stretch goals, I'm not in favor of either of them. I'm not really concerned with the length of the game; if it gets much longer all that means is there will be more content I likely won't see. Adding more companions is pretty much the same: I'm likely going to stick with a few favorites and adding more just means there is more development time going into content I won't see.
If anything were to be added - and you are 100% sure it couldn't possibly affect the release date, which I don't even believe is possible - I'd say fleshing out the current companions even more would be the best bet. You probably can't spend too much time making the companions better. (Well, except if you spend enough time to delay the game. Then it's too much.)
I think someone on the first page mentioned: can we vote for getting fewer things overall and have the game come out faster? Because that's what I would vote for as well. There is always room for expansions and DLC and user mods and whatever. The core game just needs to have a solid foundation on which to build.
