Search engine: how to open the file type with the application on the remote machine through the Apple script application as the default application for the file type

I would like to set the default file association for a file type (PDF) in an Apple Script application. The Apple Script application will open the file type on a remote machine (using remote Apple events) with a specific application (Preview.app). It does not matter, but the remote machine is a virtual machine on the local machine. I think the script should look like this:

set remoteMachine to "eppc: //elcapitan.local"
Tell the "search engine" application of the RemoteMachine machine
open ("/Applications/Preview.app" as a POSIX file as an alias)
tell him at the end

set pathToLocalOnRemote to "/ Volumes / cajal"
repeat with fn in argv
Tell the application "Preview" of the RemoteMachine machine
open pathToLocalOnRemote & fn
tell him at the end
end of repetition

What is not clear to me is, what really happens when you open a file type (PDF) in the Finder? The default file association will specify which application to use. Within the application, is there only a binary called that gets a list of file names as its argument? If so, is this binary like a command line binary? In summary, can I trust that Finder will execute my script analogously to a command line call with a list of files as an argument? Also, will the list of file names be given as the absolute (complete) path?