If you have any number of games, and they are installed you can make a Mod
to draw any information from them (graphics, text, sound, etc...)
provided that your mod can interpret them, hence it helps if the games are from
the same stable, so to speak.
(it gets more messy, but not imposable to do Icy and F4)
It would be probably easer to do it from scratch.
However F3 and F4 have lot in commune. Yes some things are done different, but lot of resources are similar, and with some conversion usable.
From laws point of view, since you own both F3 and F4 there is no arguments.
Please remember that End User Licence works both ways.
Providing you aren't doing it in public, or making profit from it.....
how you are going to use their product is totally after you.(full stop)
Of course that excludes anything criminal you may want to do with it.
(like breaking DVD and poking someone's eye with it)
PS: there are few mods that do that in a smaller way already:
Example: In F4 I got juke-box mod that I can make play my own music to it.
Modder doesn't give you that, I have to supply my own Pink Floyd.
But it works: I got original music and F4 AND I get to listen what I want.
I hope this answers you question, drawing resources on something you have
legal licence for, isn't a crime.