I would try it like this:

remote = LaunchKernels["ssh://arnoudb@192.168.1.236/usr/local/bin/wolfram"]
ParallelEvaluate[$ProcessID, remote]
ParallelEvaluate[$MachineName, remote]
ParallelEvaluate[session = StartExternalSession["Python"], remote]
ParallelEvaluate[ExternalEvaluate[session, "
import socket
socket.gethostname()
"], remote]

Note that RemoteEvaluate launches and quits the kernel every time (it's a one-shot kernel evaluation) so that's probably not what you want if you want to execute multiple commands