Guys, need some help to get a camera for my gf, who wants the camera to be small enough to be carried around yet flexible enough to be fitted with various lenses for some serious photography when the need arises.

Type of camera/lens/accesories : mirrorless / micro 3/4
Budget: 3.5k
Your Location: pj
Preferable brand : any
Type of photography u want to do : still learning so basically all types
Any specific models in mind? : pana gx1, nikon j1/v1, olympus ep3 series
Any specific features u want? :

any suggestions?