we have a topology like this:

the separate isolated 1G physical link between esxi and switch EtherChannel just for veeam backup traffic.
on every esxi separate vmkernel port by management enabled for veeambackup traffic.
veeam backup traffic subnet is separate from production.
veeam backup server is a vm on esxi6.
my questions:
1- my vcenter server ip is in production subnet and not in veeam backup subnet and we don't want the following any traffic from any subnet to veeam backup subnet. as a result, we can now just add esxi directly in veeam backup. can we add another interface and ip for vcenter to connect to veeam backup?
2- we bound two 1G LINK in EtherChannel from each esxi host. is this really doubled bandwidth in backup? is this really achievable? during backup just one link has traffic.