edit: missed adding the quote for context …
While obviously since I’m not them and I don’t know for sure I would expect that is a lower priority for limited time than making the code work. That may be an area where we of less skill in code development can help if we choose to. If you are familiar with how parts go together you can likely document it and the developers likely don’t need the documentation and are focused on developing the code. Manpower willing to donate time is what Fritzing needs most. There is more than enough work for anyone willing to help.
This one is actually a bug in parts editor (which I have a fix for). If you edit a part, click export as new part then export the new part from the mine parts bin and exit Fritzing, it will not actually delete the part created by parts editor. If you then try and reload the exported fzpz file (without doing anything to it outside of Fritzing) you will get the “already a part with that name” error (even though there is no such part showing in the bin that you could delete). When parts editor creates the new part, it currently does not register the files with the main window that will delete the files when you say don’t save on exit. Since parts editor doesn’t delete the files and mainwindow.cpp doesn’t know about them, the files stay in the bin and you can no longer load that part again until you manually remove them (which you can’t do from fritzing because internally they aren’t completely there). That said, I think this is now a dead end and effort should go in to the new project. Reading between the lines (and from stuff I’ve seen elsewhere, and thus maybe incorrect 
), I think Qt in the new project is being replaced by html5. The reason I think that is there is a white paper on the Qt site about why Qt is better than html5 which tells me that at least some of the Qt functionality is available in html5. As noted, I’m ignorant and could be wrong here.
No, schematic must have the same number of pins as bb and pcb views or the part won’t work. You can (as you did in the linkone board) stack the pins on top of each other (which I don’t like) but you must have all the pins for the part to work correctly (unless you do some manual editing in the fzp file and know what you are doing). This is what causes the part to be entirely red when loaded, pins now assigned. That is usually how I start a new part, by editing either the generic IC and changing it to the number of pins I need or doing the same with a generic header. Then all the necessary connectors for the part are in the xml and I can edit the svg and put the pins where I need them.
Yes it is likely a bug. I must have discovered that long ago and put it on the list and forgotten it. To export a part from parts editor I edit the part then save it as a new part (which puts it in the mine parts bin with the bug noted above) and then right click on the part in the parts bin and click export part which writes the fzpz file to the file of my choice outside Fritzing. I then unzip that modify the svgs and reload the part (after deleting the left over files from the bug in the user directory) to Fritzing to check it.
Peter