Can MultiWAN use the LTE modem?

I read that the SPF and WAN are not configurable at the same time, but can the LTE modem be included in a MultiWAN config?

You may re-use LAN-Ports for Ethernet WAN. So SFP + Gigabit ethernet is still possible. Limiting througput to 1 Gigabit total though.
Adding a LTE interface to OpenWRT’s mwan3 should work.

The throughtput don’t have to be limited, there one dedicated GbE link to WAN port/SFP cage and two more lines to the switch chip. You can set up switch chip to pass through one link to one port so you get one separate GbE each WAN plus one separate GbE for LAN.

I meant 1 Gbps per direction for the basic configuration SFP + 1 GbE for WAN + 1 GbE for LAN. So maximum throughput to LAN is limited to 1Gbps if only using one port for LAN.