I installed nwdr15.img and found that AX.25 was running very well using your scripts ax25-start / ax25-stop.
In order to complete my system configuration I added a script creating an axudp device for using AX25 over IP/UDP via Internet
or via HAMNET (a high speed Ham data network using WiFi used in Germany and France).
I called the attached script ax25ipd-start.sh. It must be used after ax25-start.
In order to work, the configuration needs /etc/ax25/ax25ipd.conf file.
I found that the distributed one is fine, thus I just made a copy of ax25ipd.conf.dist to ax25ipd.conf in the same directory.
There must also be an axudp port declared in /etc/ax25/axports file. For this port I set speed to 115200 and paclen to 253.
This axudp port may be used by AX.25 applications such as Node, FPAC, BBS linFBB.
listen -chat will display all AX.25 network trafic including udr0, udr1 and axudp.