Cannot Receive engine speed from low-can

I am trying to develop my app which is using speed and engine speed from low-can in 8.0(Halibut).
When testing the speed and engine speed, I have encountered the following three problems.

1.Low-Can Started Without VCAN Port

The low-can service started when the board started. But configuring the vcan port takes time,

so that low-can started without vcan port happens often. And then my app will not receive any can data.

I have tried to modify the config.xml.in as follow,

and it will works. Is this modification OK? Is there other way to make the low-can start after vcan port created?

2.Cannot Receive Engine Speed Data

The engine speed cannot be set by the command [cansend vcan0 3D9#ffffff]. Error info:

Aug 02 05:28:47 m3ulcb afbd-agl-service-can-low-level@7.99[4057]: NOTICE: [API low-can] is_engine_on: engine.speed CAN signal found, but engine seems off /home/aglcompiler/AGL/agl-8.0.0/build/tmp/work/aarch64-agl-linux/agl-service-can-low-level/8.0.0-r0/git/low-can-binding/binding/application.cpp:110,isEngineOn
Aug 02 05:28:47 m3ulcb afbd-agl-service-can-low-level@7.99[4057]: NOTICE: [API low-can] is_engine_on: engine.speed diagnostic message found, but engine seems off /home/aglcompiler/AGL/agl-8.0.0/build/tmp/work/aarch64-agl-linux/agl-service-can-low-level/8.0.0-r0/git/low-can-binding/binding/application.cpp:130,isEngineOn
Aug 02 05:28:47 m3ulcb afbd-agl-service-can-low-level@7.99[4057]: WARNING: [API low-can] signal: Engine is off, diagnostic_messages.engine.speed won't received responses until it's on /home/aglcompiler/AGL/agl-8.0.0/build/tmp/work/aarch64-agl-linux/agl-service-can-low-level/8.0.0-r0/git/low-can-binding/binding/low-can-cb.cpp:206,subscribe_unsubscribe_diagnostic_messages

I have tried to modify the source file application-generated.cpp as follow,

and then my app can receive the engine speed. Is this modification OK? Or is there other way to make my app receive engine speed?

3.Multiple Apps Cannot Get Can Data at the same time

If I launch the dashboard first, then launch my app. Only the dashboard app can receive the speed info.

Conversely, only my app can receive the speed info. How to make all the apps which are using low-can receive can info?