I seem to have gotten carried away installing Preheat plugins (BetterHeaterTimeout, Preheat Button and Smart Preheat). It appears to me that they will all coexist, could be wrong?
Will BetterHeaterTimeout override the heater timeout in Marlin (I'm running 2.0.5.3)? Any reason why I can't add a beep to the After GCode? (I have this bad habit of hitting Preheat then getting lost in something else).
It might be better to post the symptoms of the original issue that caused you to install (lots of) preheat plugins. Preheating and heater timeouts should be two separate issues with different reasons for wanting to solve each.
If you had posted this in Get Help instead of General you would have been given a template to fill out which (when done correctly) gives us the information we need to help you.
I appreciate that it must be very frustrating when people ask for help but do not supply sufficient information. Given the 3 questions I posed I'm unsure as to which log to post. Please note that I have no issue with any of the plugins, just looking for guidance.
If you want to work on it yourself, that's cool. The plugins you listed may coexist, but they may also contain redundant code. Examining the sources will help figure that out.
Don't know about overriding Marlin. Again examine the sources.
I can think of no reason why you can't add a beep.
If you decide you would like some additional help in the future, all the logs are better than none of the logs. Complete copies of the octoprint.log and serial.log (after being enabled) contain lots of useful information for both you and us.