Whether or not Future will protect the paint from being "rubbed off" depends on how well the paint is bonded to the figure. Many people make the mistake of thinking that applying a strong coating over a weak undercoat will improve the durability of the system. It won't.
Future is very tough, very strong, and bonds very well to almost anything. It also shrinks as it cures—which is why it looks thick going on but shrinks down wonderfully to the surface. If the underlying paint is poorly adhered to the substrate, Future may crack it or peel it off.
If you want a clear flat coat, mix Tamiya XF-21 Flattening agent with the Future.
Clear lacquers often contain an alcohol solvent that will attack acrylic paints, often very aggessively.
What acrylics are you using on the miniatures, and what are the miniatures made from?
Wash the miniatures in a warm solution of Simple Green and water (an ultrasonic cleaner is ideal for this). Rinse thoroughly. Resin parts should be wiped with denatured alcohol immediately before painting, just as a precaution. Metal parts can be etched with a mild acid solution (vinegar is fine) for about 5 to 10 minutes, rinsed, dried and painted.