Could making minor changes to a webpage but still leaving the adsense ads in the same places affect adsense revenue?
Yes and No.
Yes, any changes no matter how small have the potential to break other things on your page. If your changes broke something relating to the ads then it can have an impact. An example would be changing the style in your CSS from a variable height to a fixed height, and that change would also apply to a parent div of a responsive ads.
No, assuming that you haven't broke anything, it would be very unlikely that small change would impact AdSense revenue. Given the high degree of variability in Adsense revenue it would be even less likely that one would be able to attribute changes in revenue to these minor changes on the page.