My advice would be go for the Eagle Eye 9 for the bow. I picked up an Eagle Eye 9 near the end of the season last year, and while it's not on par with the FS or earlier HDS units as far as adjustability, it's a good basic unit, with as you put it, "AT light" If networking is important to you, you could always add an FS7 at the bow at a later date.

I'm currently running an LMS 322C at the bow along with my Eagle Eye 9, and an HDS Gen 2 Touch at the bow. I'll be replacing the LMS unit with an FS7 with an HDI transducer before ice out this year. FS7 for chart and 2D sonar and down imaging, and the Eagle Eye 9 for forward facing or down facing sonar, only. I also have my Eagle Eye 9 transducer on a separate pole mount that I made. Having its' transducer separate from the trolling motor make it so much more useful IMO, because I can aim it anywhere I want and leave it there, without out worrying about losing boat control because I had to turn the trolling motor because of wind or water current direction.