Health Monitor via MGMT (DCDs)

Hello, I use BIGIQ and DCDs (2 DCs deployment) to collect data + WAF Events.
I have a pool of my BIG IP DCDs (MGMT subnet) in the BIGIP configured as HCL.
I configured an MGMT Route, but the health check goes from the data interface self-IP.
Can a static route for TMM routing be configured to this destination or to choose which IP will monitor these DCDs?
*It is not possible to create a TMM route with IP GW that is not associated with this Route domain (MGMT subnet)

Another question: If I don't have other options. When one of the DCDs pool members is down (for example, time out), does the BIGIP mark this pool member as unavailable and forward the request to the next available pool member, depending on the TCP server profile? Or will the requests fail?
Maybe another load-balancing method will be helpful here.
Thank you!