The D3300 and D5300 have the same image sensor, so the image quality is effectively identical. The D5300 has more autofocus points, a flip-out screen and GPS as notable features that the D3300 does not
The D610 is our only full-frame camera, meaning it has a larger sensor and will have significantly better image quality than the D3300 and D5300. The D610 has a slightly higher continuous shooting frame rate and significantly better low light performance than the other two. One major difference of full-frame versus crop sensor cameras (such as the D3300 and D5300) is that the same focal length lens will appear as a wider angle on a full-frame camera
The Sony a6300/a6400 has roughly the same image quality as the D3300, but is more portable, has much faster continuous shooting frame rates, has faster autofocus, and can shoot up to 4k video, as well as 1080p video at 120fps for slow-motion
The menu system is expansive, and changing settings on the a6300/ a6400 can be a chore
Nikon D3300/D5300: the 35mm and 50mm primes are good
Nikon D610: the 85mm prime and the 24-70 f2.8 zoom lens are good
Sony a6300/a6400: The 35mm prime is good, the 18-105 can work too