lowrance unit compatibility

I have a Lowrance elite 7 HDI on the console and would like to add a second unit on the console with side scan & downscan that can share waypoints with the current unit.  I also want to add a bow unit that can also share waypoints.  So my question what units can still connect with it?  Chirp, Elite Ti, Elite Ti2, HDS gen2?  Mainly looking at used units like an elite 7 at the bow and a HDS 10 for the console.  

Any information and advise would be welcomed

Thank you