Both models was spotted on TENAA site.
I informed about Galaxy On7 not so long ago but now we have some additional informations:
System: Android 6.0.;
Screen: 5.5" 1080p, IPS;
SoC: Snapdragon 635;
RAM: 3GB;
Storage: 32GB;
Cameras: 13/8MP;
Battery: 3300mAh;
Size: 151,5x74,9x8mm;
Weight: 167g.
As for Galaxy On5 (2016) we didn't had any informations earlier but as we can see it will accompany On7 (2016):
System: Android 6.0.;
Screen: 5" 720p, IPS;
SoC: Snapdragon 617;
RAM: 3GB;
Storage: 32GB;
Cameras: 13/8MP;
Battery: 2600mAh;
Size: 142,8x69,6x8,1mm;
Weight: 142g.
As we can see this year version are much better then originals from last year and even from their "pro" editions.
From picture above you can deduce that models are identical in terms of design so quick tour: top one is On5 and bottom On7. Price and launch date isn't known.
Source: gsmManiaK (Polish)