Multi Building Single ISP FIBER FEED config help

Current Configuration:

current barn with living space:

1 GB MIDCO ISP fiber into their HITRON  NOV2004 modem,  that connects to a current Orbi RBR750 router and a RBS750,     

adding a new house 250' away from barn

using configuration up top we have also added a an 8 port TP-link TL-SG3210 v3 switch, which is picking up the CAT6 cables in the barn, and runs fiber over to another 16 port TP-Link TLSG2218 which receives the fiber from the barn.

I've purchased a ORBI 960RBKE963 which has two satellites,   the problem i'm having is i can't get the 960R router to connect or get internet through the switch in the house.

i've tried doing the whole connect directly to a computer and change into access point mode but it says i need an internet connection to do that, and does not allow me to go through that configuration to do so.  

am i better off returning the 960 and buying dedicated Netgear access points for the house to run off the switches, and if so, do i need to change switches to also have POE, as well as the SFP slots for the fiber backhaul to the barn.  

i've really enjoyed the 750 orbi system so far, and was really hoping the 960 for our main home was going to be something to go with...    in talking with my ISP they won't allow me to run a second line / modem, as that was going to be my first choice.

any help would be appreciated.