#1, check the /opt/emc/scaleio/gateway/webapps/ROOT/WEB-INF/classes/gatewayInternal.properties file and look for "gateway.token.no.activity.timeout.in.seconds=600". 10 minutes is the timeout by default (This is from 2.0.1.3 Gateway). I'm not sure if there is a tomcat timeout that might interfere with setting this higher, but you are welcome to try changing this and see if it makes a difference. Restart the gateway when changes are made.

#2, The only ESRS piece that looks like it will help here is "/api/types/Esrs/actions/checkConnction"

#3, ScaleIO isn't aware of the VMs on the OS. This will need to be a PowerCLI script or something similar to query that information.

#4, To check and see if RAM Read Cache is enabled is a little trickier, as there is no specific check, other than from the --query_all correlating rest api call (/api/instances). So in that case, you would have to make that call and then parse the output for whichever component you are interested in (Pool/SDS/Volume).

Hope that helps