Thank you for the helpful comments. I re-checked the settings this evening and I think the answer to my earlier question is likely 'confirmed, it should work'.
Some responses to questions asked in the thread:
1. We did indeed have Dlink related drops at the competition which looked, I think, like the 'e-stop bug'. The issues with autonomous were after this (once we replaced the flaky dlink) - thanks to the Qualcomm ref and also to Mike from 971 that helped identify that!
2. In response to billbo911 - FWIW - the Rio cannot be configured with a netmask of 255.255.255.0 if the IP is 10.TE.AM.2 and the GW is 10.0.100.1 - so I configured the netmask to 255.0.0.0, and the other settings per your post (.5 for the chezy-arena host and .5 for the DS).
3. As for the DS failure log during matches. One of our team might be able to dig this up from one of the laptops.
Note, again, that the Dlink is not in play in this setup. Everything is going through a single switch (DS, Rio and Chezy-champs), pending our resolution of the bridging problem with the Dlink.
So.. there is some progress this evening - I got the message on the DS saying 'begin FMS control'. However, when we click on this, the chezy-champs crashes per the below (chezy-champs running on a mac, leaving the GUI as attached):
http://imgur.com/a/lffFd
2016/10/03 21:35:00 Rejecting connection from Team 5026, who is not in the current match.
2016/10/03 21:35:02 Accepting connection from Team 5026 in station B1.
2016/10/03 21:35:02 Driver station for Team 5026 connected from 10.50.26.5
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x4010f25]
goroutine 11 [running]:
panic(0x4620a00, 0xc42000c0d0)
/usr/local/go/src/runtime/panic.go:500 +0x1a1
main.ListenForDsUdpPackets()
/Users/pfairban/go/src/github.com/Team254/cheesy-arena/driver_station_connection.go:82 +0x2b5
created by main.main
/Users/pfairban/go/src/github.com/Team254/cheesy-arena/main.go:25 +0x9f
dhcp-157:cheesy-arena.v2016.1.0.osx xxx$ ./cheesy-arena.command
goose: no migrations to run. current version: 20140823193501[/i][/i][/i]
Additionally, we tried running cheesy-arena on a PC. This gave us an error of 'bind: 1160: Only one usage of each socket address is normally permitted'. This was after a fresh reboot on the PC.. so not clear what would be causing this.