it certainly will be interesting to see if logan dies or not, i know its assumed he will because jackman is leaving but there is a possibility he doesn't die.
As for an end credit scene, i assume it has to take place around the time of logan as i can't see them jumping back years for a random end credit scene if it doesn't connect in some way to the film we watched, just like the end credit scene for X-Men: apocalypse.
Edit: Oh it says Reynolds was in the scene... So could we see Deadpool in the logan period?