Q1: I have both FS2020 and FS2024 installed. If I install a new versions of FSUIPC7 into FS2020, can I then just delete the old FSUIPC7.exe from FS2024 and then copy the new FSUIPC7.exe from FS2020 and paste it into FS2024? Or do I have to go through two complete install processes?
No, you cannot do that. If you are using separate installations of FSUIPC7 for MSFS2020 and MSFS2024, run the installer twice. The installer installs more than just the exe (e.g. WASM, Documents, autostart, registry updates)
When installing FSUIPC7, there is an option to either have FSUIPC7 start automatically with the sim, or via a batch file. Where is that info stored in case I want to make a change, or if FSUIPC7 is no starting automatically as it should?
This information is not save anywhere - your choice affects what the installer does. If you want to change this, you need to re-run the installer.
However, there is no reason at all to use the batch auto-start method these days - that is just a hangover from earlier days. There should be no issues with auto-start via the EXE.xml method. If this is not working, see the following FAQ entry, which contains all information available on auto-start issues (any support issue raised on auto-start will be referred to this and closed): https://fsuipc.com/community/fsuipc-faq-issues/msfs-fsuipc7-auto-start-with-msfs2020-2024/
John