How are devices installed, connected, configured?
It must be possible to flash firmware in-situ. Devices will likely be installed in IP rated boxes up masts and on roofs where access may be difficult. WiFi may be acceptable but wired probably better, for reliability, and to avoid requiring the installation of a WiFi access point on a roof also.
Meshtastic does not provide OTA (wifi) flashing for ESP32 devices because of code space requirement. It could be done over serial (RS422), with a reset line maybe, or with another ESP as programmer.
https://www.improv-wifi.com/ - Configure wifi over Bluetooth LE or serial.
OpenCPN will interpret WPL NMEA sentences as AIS type targets. This was implemented to support APRS receivers, but presumably would work with any source, e.g. NYAN.
I don't know about getting weather station reports into it though.
It has code for parsing weather data from AIS: https://github.com/OpenCPN/OpenCPN/blob/999ab9c1bbaf05ff1fdf917345f8e803685425f4/src/ais_decoder.cpp#L3373
Also NMEA2000 weather report parsing. Don't know if it does anything with it though.
Issue developing AIS WX parsing and display.