The most surprising thing was how Milan missed the opportunity to be in the top 8 in the last round with Dynamo Zarub, for whom this victory was very important, but despite the victory they were left out. Probably for me it was more unexpected to see Lille and Aston Villa in the top 8, and Real Madrid were still unlucky to achieve this goal, it’s bad that they will have to play additional games, but I have no doubt that they will beat their opponent, because they are in excellent shape now.
Milan is playing with 10 players, so it will be hard for them and they're not really strong, the proof is Milan not able to reach top 5 in Serie A.
Both Lille and Aston Villa are very lucky, they lucky in drawing since they meet many weak teams and they're also lucky in the match since they can beat big teams like Bayern Munich, Real Madrid and Atletico Madrid.
It's always experienced teams that can qualify to the next round, even the big teams are in struggle, the small teams still not able to beat them.
The next round is just for the play off teams, teams that were positioned from 8th to 1st will be relaxing. For Lille and Aston Villa, though they had easy teams as you said, but they really tried in beating them and getting to the position at which they found themselves now. It likely that the Play offs will start in two weeks time.