The van on the bridge with the mast extended is most likely a Mobile Cellular Tower to help cover high usage areas.  They drive them to concerts and park them in lots during parades, any time there's going to be a whole ton of text/voice traffic that needs to be around and reliable.  I am guessing they were getting iffy service,  they move one there and it runs a local tower and has a single high speed uplink to the network.

Is that what people are guessing that it is a drone jammer or something?    

Drones run on the open 2.4 and 5GHz bands (freqs WiFi uses as well) and jamming one isn't a simple matter as they're spread spectrum, you'd need to white out the whole band to have an effect, and if the drone is linked via cell phone or starlink or other similar high end comms, there's no real jamming it.  The new ones can be programmed with a flight profile and use GPS and IMU to travel a path and record and return to be downloaded as well.  They're handy for terrorists like that.

Exactly 1 month later, ship still there, half a channel and 2 pseudo-channels

I'd have thought the ship would have been a priority pulling the wreckage off of it and getting it out of the way to make room for the cranes.  I suppose that's why I'm not in marine disaster recovery.