Hello Christian,
If you create a Multitech Support Portal case at https://support.multitech.com they can help you with some of these customizations. In short:
wan-manager: is a process that is tightly integrated with WAN failover on the device and also with management of DNS and other WAN related things. I don’t know that you should touch that one.
led_cd_ss is a script that is managing the LEDs on the device (at least some of them including the signal strength and carrier detect. If you are not using cellular, you might get away with disabling this one.
If you are not using Device HQ, and don’t plan to, then you can disable monitor-annexcd by disabling remote management.
mgsgps: this daemon is used to get GPS data from the u-blox chip on the device. If you do not care whether GPS data is sent to Device HQ or displayed in the Web UI, then you can turn that one off.
Jeff