I tried numerous combinations of acceptable kernels and roms no dice through multirom for ubuntu touch unless it can be installed manually and not through the app somehow. Once you have proper a multirom twrp, multirom zip, and kexechardboot accepted kernel it is still possible to multiboot any other roms aswell as sailfish os. The multirom app itself is the problem because it always says now "failed to get information about the updates". The only way it was possible was before was clicking the option to install ub through the app which no longer appears unfortunately. It would be great if someone could revive this or modify the app to work again. If anyone does still have it configured this way don't uninstall it or you'll be pretty bummed like I was when I went to install it again.