If you are very sure that the bendix is really engaging when this trouble happens but the starter motor doesn’t spin then the trouble could only be from a few things. Either the solenoid contacts are bad, connection to starter windings is open, or the main battery lead to the solenoid is faulty. You have already replaced the starter so that should eliminate the solenoid contacts and connection to the windings. It just leaves, as Curly (City Slickers) would say, “that one thing”.
Sorry to hear your van has been a problem. We have had our '02 Town & Country since new and have little problem with it. There were a couple of electrical issues that happened while under warranty but we got those resolved. One of the problems involved replacing the wire harness for the engine. I’m very glad that was covered by warranty.