The Westells will work just fine as MOCA bridges.
Yes, leave the rev. I as your primary router.
"I always seem to get 'orange' NO INTERNET access on the secondary routers"
It's normal to get "no internet" on the secondary routers. You're not using their WAN connectivity. You are creating a LAN bridge to the primary router.
"I can't seem to get the router "configurations" set-up correctly"
Where are you having trouble?
"Any advice on a Step-by-Step Youtube video or how-to ?"
Follow part 2 of this FAQ:
http://www.dslreports.com/faq/15984
Keep in mind the Westell routers are 802.11g only. If 802.11n coverage is important in areas not reached by the rev. I, then the WCB3000NK01 may be a better solution for you.