I love this game, but I don't fucking get how they still have these awful glitches at this point. The stranger that gives the Fundraiser quest vanished. I rode into Saint Denis to try to get some of the stranger missions there. Accidentally did that shit where I tackled someone instead of getting on my horse, got chased all over the city for my bounty of $2.50 and it seems to have made this stranger not appear anymore.
Unless it's a well known glitch of strangers permanently disappearing, every story-giving stranger appeared for me throughout the game though sometimes they'd come and go. Some are time based, at least two of them are around Saint Denis, and others are bounty based so they won't show up if you've caused a ruckus in that area for a while. But, within time, they all come back as far as I understand.