The feedback doesn't mean he can't be trusted to send merits, and others may even disagree with the feedback.
Yes, but Im sure the feedback doesnt give him points, either.
I haven't looked into his merit history so I can't say whether he would be a good choice or not, but merely having negative (even from me) shouldn't 100% exude you from ever being a merit source, especially if you're an active member and are regularly giving out accurate merit for noteworthy posts. I'm sure theymos is intelligent and impartial enough to take all the available evidence and make up his own mind whether he should be a merit source or not and it's only him that gets to decide who is made one or not currently.
I dont know how theymos thinks, but if I was him, having negative trust from you would make it at least less likely to add him as a merit source, because, yes, not looking trustworthy for deals doesnt mean he can do a good job as a merit source but if he misbehaved as a merit source, I couldnt say I was completely surprised.
If I was theymos I would think like this:
OTOH, red trust for the other things seems to indicate a general tendency to easily sell out for a few bucks.
Wich is definitely not a quality I'd like to see in a merit source.
....
Maybe in one or two years, when the OP has established some solid reputation.
Theres no hurry to add him as a merit source, as there is no hurry to add anyone. I think even less in this case.