Hi,
Will workbench 3.1 work properly with ROM 3.1.4 installed on a A1200?
You should not mix kickstart versions and disk versions. You will sooner or later face some issues.
That said, if you insist (I see no reason why), you can make that happen:
Install 3.1 and add workbench.library and icon.library from the 3.1.4 OS.
Make sure both libraries have the "p" protection bit set.
And then just boot normally, no LoadModule stuff is required.
Again, this is not adviced and you will most likely end up with problems in the long run. But as an experiment, it can be done.