This is normal. It’s just Linux trying to be strict about USB interface numbering. Just a pointless warning which can be safely ignored.
dhclient does not support the qmi_wwan type of raw-ip interface. It can only work with ethernet (like) interfaces. You may have more success with e.g. udhcpc from BusyBox.
The MC/EM74xx has no 802-3 support, so changing the data format is not an option.
You can retrieve the IP config using QMI and congure the interface based on this instead of using DHCP. Try something like