Vim process stops after executing an external command

Don't use an interactive shell to execute commands. (That's the i in -ic.)

The default shellcmdflag (-c) should work just fine.

If you are specifying -i in order to get bash to read your .bashrc file (which is a side-effect of starting an interactive shell), then you would be better off just telling bash to read a startup environment script. Quoting the bash manpage:

When bash is started non-interactively, to run a shell script, for example, it looks for the variable BASH_ENV in the environment, expands its value if it appears there, and uses the expanded value as the name of a file to read and execute. Bash behaves as if the following command were executed:

          if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi

but the value of the PATH variable is not used to search for the file name.

You can set environment variables inside vim with :let