I’ve not tried it but I would expect the issue to be the web server more so than Allmon itself. Apache or the web server of your choice would need to run on something other than port 80. Install your choice of web servers, change the port to 8080 or something PiStar is not using, put the allmon files in the server’s webroot and you should be good to set up allmon.
But honestly, I’d say just get another Pi and dedicate it to AllStar.