@joshopkins
Seems all the settings you did are correct, apart from the push-route commands in the default options. These do the same as the "local networks" setting does, which is the preferred way. You shouldn't have both settings.
Ensure that the access is allowed by rules on all incoming interfaces. Means on the OpenVPN interface at B and on the IPSec of A and C.
To see what's going on, sniff the traffic on the involved interfaces, while you try to access a remote IP from an OpenVPN client.