Regarding echo, one can use same kind of baresip accounts file as with play, such as
sip:echo@test.tutpro.com;auth_user=echo;auth_pass=xxxxxx;outbound="sip:192.168.43.82:5060;transport=tcp";ptime=20;audio_codecs=OPUS/48000/2,PCMU,PCMA;regint=600;pubint=0;regq=0.5;sipnat=outbound;answermode=auto
The difference is that in config file, these lines are needed:
audio_player aubridge,pseudo0 audio_source aubridge,pseudo0 module aubridge.so module_app echo.so
-- Juha