Do you have block diagram for SBM-XEM-X10SM? I see two RJ45 ports on it, The manual is not clear about that both ports are connected with 10Gb switching matrix, or only one. Is the second physically separated
(not VLAN only) for management module (BMB-CMM-002)?
The 1G port(bottom one) is connected to other 10G ports on the switch, so you can use it as you described below for low Bandwidth traffic. The only risk is that the port might get overloaded as it connects to multiple 10G ports.