the routing_point.xml file is enough to share. Of course, you and you friends have to have the NavigatorFree from MapFactor. On other system it won't work.
Creating a gpx-file is better done with an external tool, so like www.osrm.at - routing maps. You can export as gpx. But gpx-files aren't for routing, you just can show the track on the map and follow it on your own.
To create an other icon, I'm afraid, that is is not possible (as far as I know).
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