I think it's a bit unfair to infer anything about their character based on their on-field performance.
Everything I've read about both of them has spoken highly of them. I think they're both hard workers and have bought in, no attitude issues. I think they care and want to perform well.
Agholor is ultra athletic but has issues with his hands and balance. I like him, he flashes, but I'm not sure he's reliable. I don't trust him to not fumble the ball, either. I wish they would use him more on end arounds and LOS touches but I think that's the concern (potential fumbles).
Jonnu I think has a ton of untapped production. I can't recall the guy making any obvious mistakes or errors. Maybe a fumble. Jonnu is almost entirely a usage issue IMO. Every time they throw the ball his way and it's catchable, he catches it and makes a play, gets YAC, gets upfield. I think he's had some issues with run blocking but he could be doing a lot more with a competent offense and good quarterback play.
Just my two cents.