Multiple Static IPs and a T-Mobile Cell Router

Can the Gold (or other models) be used with both 5 static IPs (a blcok from an ISP) on one WAN port and a (backup) T-Mobile cell-based hotspot (which can also be directly connected via ethernet to the Gold, if necessary)?

If so, are there any limitations using the static IPs? Each must be useable from the outside and get through port forwarding to various servers.