I have the same question. I don't have any Meraki device so not familiar with the API method you mentioned. We just rolled out a small Viptela deployment with hopes to take it enterprise wide.
Your not alone, I in need of monitoring Viptela equipment as well. SW or another THWACK member if you have dug deep into this area, please share your findings.
Currently we monitor the vEdge routers just via SNMP and I use undp to monitor OIDs for bfd session state, etc (adding the tloc local color enumeration as the label on each row).
Would be nice to be able to interact with vManage via its REStful API directly or have events from vManage push to NPM but we are not there yet.
OIDs I use are:
I then have this trigger alerts based on the tloc local color having an Up BFD session in the ListState table (we have a dual hub/spoke policy) and triggering an alert if it doesn't. Some of my alert logic isn't all the way there yet though if the result is a table that does not have a row for the color i'm looking for in it (due to physical interface down, etc).