Kinda confused as to why you’d want to do this. The point of 3.1.4 ROMs is to run 3.1.4 .
There is lots of software that came on floppies and that were meant to run from those floppies, and the components on those floppies were typically from OS 3.0.
So the question is - are these expected to still boot well with a 3.1.4 kickstart, provided that workbench.library and icon.library can be loaded from elsewhere?
(not to mention all the "illegal" OS3.1 based preinstalled hard disk images "floating around" with complete environments for developers, for musicians, for gamers etc - you know, all things useful and fun)