a) Is there a POL way to checksum the installer of the software or is that no recommended practice?
(and then issue a warning in case the specific installer checksum is untested. ).
Is there any way to generate script specific automated feedback to the script mantainer like for instance when a software version with another checksum pops up that also runs?
b) If there are games that run completely flawlessly under recent Wine, is it possible to generate a POL script without much ado? In other word, is there a default template or installer generator form for such simple cases?
For your second question, this is not really possible with POLv4. However, POLv5 (experimental) has a scripting template system, so you can create basic scripts really quickly. Example: https://github.com/PlayOnLinux/Scripts/blob/master/Graphics/Photofiltre/Online/script.js
Regarding the checksum, we are not doing it currently but it could be a great way to improve stability.