Tricky one to compare using those numbers I think but I enjoy getting all geeky looking at figures, appreciate the post!
Is matches the best way? I'd have thought minutes would be the way to go. All 6 of a team's front 6 could easily play the same match. 3 starting, 2 on after 70 minutes, 1 on for 5 minutes at the end. Like for like replacements with no change in formation. They all get one apperance each. One of the others plays their starting front 3 for the whole game and only 3 of them are said to have played a match. Would think it would somewhat even out over the long run, with all the teams doing each of those roughly equally but that's no guarantee. Could skew everything, might actually look at that myself in a bit.
A big thing- where are they now? Havertz and his much improved goalscoring form since joining Arsenal compared to what he did at Chelsea. If looking at him when he joined Arsenal (can't be bothered with minutes right this second myself either), he was 19 in 91 for Chelsea, 1 goal every 4.79 matches. For Arsenal he's on 17 in 45, 1 goal every 2.65. Even at Arsenal he switched position and it was then that he started scoring to a much greater degree.
Have a look at that here, the way he explodes after moving to CF. Had he not joined Arsenal, or had he not switched position we wouldn't have necessarily thought he was capable of that or 'having enough goals in him'.
Contrast to Rashord who has scored goals in the past for us, it's been quite a long time since he has. You've got got to wonder at some point if he has that in him any more. Some players just go into a terminal decline and it somewhat looks like he might be one of them. He's 8 in 41 for the same time Havertz has been at Arsenal, 1 goal in every 5.13 vs. Havertz's 1 every 2.65. Comparing it to Havertz since Havertz played up front would be a much bigger difference again. Would hope Rashford could or can get back to being better than he currently is but we don't know, his past stats padding out his current ones in a way.
Guess it would also be important to look at who is getting the minutes. Is Jesus part of Arsenal's front 6? He's hardly played at all for them this season in the league. Who is Arsenal's front 6 anyway? Saka, Havertz, Martinelli, Trossard, Sterling, Jesus and Odegaard is 7.
Agree that looking at what the rest of the team brings to you is important and we don't offer much right now. When it comes to assists, and therefore influincing overall goal involvements that the rest of the team provide it depends on how you want your team to function to an extent though. Alexander-Arnold and Robertson have provided a lot over the years, other teams nowhere near as much from that area. Given that, maybe just maybe you can get away with different approaches, even including your forwards doing everything from a goalscoring/assist persepctive but it's not intuitively desirable. Think R9 scored a ridiculous proportion of Inter's goals once and they had a good season finishing 2nd but it's not the norm. Shearer and Sutton at Blackburn perhaps another rare one.