There is little chance for Chelsea or Aston Villa to win the title because Arsenal, Man City and Liverpool are the biggest favorite teams until the tight competition from these three teams that have a big chance to win the title. With Chelsea in the top four, I think it is quite a good achievement because with their own performance improvement that can make them in a ranking that is at least quite profitable. Liverpool is the team that leads the standings and of course this is quite difficult for Arsenal and Man City to win the title, they have new rivals in fighting for the title because indeed with the previous season where Liverpool was quite far behind but now they are performing well to become the team that conceded the fewest goals. There is a chance for Liverpool to win the league title as long as they can maintain their performance well in terms of defense and attack.
Aston Villa is more like a fluke they can able to win against Bayern Munich and reach 5th position in Premier League. Currently Aston Villa only have good results, but their statistic are actually just like a mediocre teams. A strong teams need to have both good results and performance, Aston Villa don't really dominating the match and they have bad goal/conceded ratio.
Chelsea on the other hands, have both good results and performance, so I will not be surprised if Chelsea will qualify for Champions League in the next season.
Chelsea does look more convincing than Aston Villa. But I think Aston Villa's good results are not just due to luck. Yes, they did have luck, but the victory they achieved and the ranking they achieved now is also because they have fought well. Even though they look like a mediocre team, we have to remember that Aston Villa last season also surprised us because they managed to qualify for the UCL. So it's possible that this season they will do the same thing. In the UCL, Aston Villa even proved that they are a strong team by beating Bayern. And that's not a coincidence because in the first match in the UCL, Aston Villa also managed to beat Young Boys with a landslide score of 0-3. which means Aston Villa haven't even suffered a defeat in the UCL. so I think the strength that Aston Villa has is really real and worth taking into account.