Running 400' of coax because the desert needs the internet

Hey guys. I hope you can give me some feedback and criticism on an idea I'm tossing around.

The current setup: Three buildings in the middle of the desert need internet so some scientists can submit lab results from time to time. They currently get 5Mb/second which is not enough. I've arranged to get new satellite internet out there that is 25Mb/second which will easily be what they need since their demands are so low. But my questions lie in how to get internet to all three buildings.

The buildings are each 400 feet apart. Ethernet can't handle that distance adequately, Fiber is OVERKILL for speed, cost, and also durability against the harsh desert elements is questionable (extremely hot summers, extremely cold and snowy winters). So my currently plan is this:

I feed satellite to the center building as an MDF to my main router/switch/servers/WAP etc. From that switch I use x2 media converters to go ethernet to coax, and run two lines of burial grade quad shielded RG6 in two directions to both of the side buildings. In the buildings I convert back to Ethernet and into two more WAPs.

My questions are ... does this sound like it'll work? Haha! I haven't worked with coax nearly as much as fiber so I'm unsure if the coax will be shielded enough to not get massive amounts of interference? Do I need to bury my lines to avoid interference? Will that distance have too much data loss? Should my coax media converters be MoCa 2.0 or if i can get by with simple DECA adapters? etc.

On paper when I look at signal loss numbers, and distance limitations it seems like it'd be... fine... but paper vs real life can be very different... and again I REALLY haven't worked with coax much.

I'm open to all ideas and criticism, but does this sound like it'll work?