I would be surprised if they beat PSG. I know that they have been good and they tried to make it to the quarter-finals, but I don't see them making it to the semis. I rate Emery a lot and I believe he's a top manager, if anyone can do it then it's him but in this case, the quality of PSG is way more than that of Aston Villa. Also, Enrique is not a small coach, he's a good tactician too.
If the match was a single match then Aston Villa will have a better chance because they can defend well and score a goal and qualify but a two-legged tie makes things very difficult for them to qualify. PSG will make it to the semi-finals, but I don't know if they can win Madrid if Madrid qualifies.
Aston that is in between 10th place in their domestic league, they can only try and I don't want to feel pompous for PSG, Aston Villa can't be issue an issue for them, the hardest they can go is draw or goal/goal and then from there go to penalty kick. PSG is even wise enough to know that going to penalty with Aston Villa is an advantage got them, it's a match they can complete without going further to any extra minutes of their game that will lead to any story.
The only place I think PSG might be hook is there next round after this stage of Quarter final, Real Madrid are now beginning to move like the way they did in 2017. When every one thinks they aren't going to make it, they prove everyone wrong that they are still in the game. People aren't that interested in this particular one, it's the next stage because no way Arsenal can remove Real Madrid from this stage, it's Arsenal that will be parking home after the next stage in my opinion.