Can I still use Apigee Edge's features with custom Oauth2 authentication?

[#1]

If we have our own authorization server that provides OAuth2 tokens, would we be able to tie these tokens back to Apigee's developer apps with either the OAuth2 client_id or the actual client's id?

An example flow with password grant would be:

1. We set up client credentials for an API consumer on Apigee
2. Consumer would use the client credentials to request a token from our auth server
3. Auth server "syncs access/refresh tokens with Apigee client" (?), sends back tokens to consumer
4. Consumer uses the access token to request for a protected resource proxied through Apigee but validated by Our Auth server

On Item #4, is it possible to have Apigee read the access token for analytical purposes and not validate the token; for such things like request metering per developer apps?