Finally finished this lab, but experienced and oddity...
I saw the routes in the CE routers for the remote CE but wasn't able to ping. I even sourced my pings from a loopback that was being advertised in the CE-PE routing protocol. Weird.
Other than that, this was an interesting one, the 2 routers that join the 2 BGP ASes, were configured as eBGP peers and configured to send-label. Then the the eBGP VPNv4 relationship was farther spread apart, it was actually a peering of the PE to PE across 2 BGP ASes.
All in all, a good lab, but I'm troubled by why I can't seem to ping from CE to CE in either VRF.
On to the next one.
UPDATE------------ Issue resolved.
The problem was something so silly, I didn't have MPLS IP configured on R4, R5, and R6 in my ISIS domain. A good lesson, if your control plane looks good (ie your routing table) then the problem has to be in your forwarding plane. Thanks to Vignesh for his help.
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