MG version of localized font processor doesn't work as intended in MG pipeline tool

Thanks to @KonajuGames’s help, I was able to rebuild the localized font processor (http://xbox.create.msdn.com/en-US/education/catalog/sample/localization) to make it work with the new MG pipeline tool. But there is one big issue: the localized font processor doesn’t use default system fonts for characters (e.g. Chinese and Japanese) that are not included in the target font, which leads to ugly unrecognized character blocks in game. This was not the case with the old MG pipeline Visual Studio solution, which created fully functional localized fonts.

If it is not something easy to fix, I wonder if there is a way to update my previous MG pipeline solution or create a new pipeline project, so that I can build the localized fonts I need in Visual Studio? (referencing the MonoGame.Framework.Content.Pipeline.Windows project in my old MG pipeline solution creates errors and doesn’t seem to work anymore)

Edit: I just realized it was the MG Sprite Font Processor that was causing this issue (i.e. not using default system fonts for characters that are not in the target font). The Localized Font Processor only creates a list of characters and then uses the Sprite Font Processor to create the desired font.

Can someone help me with this issue? This font problem has been preventing me from updating my game, which crashes in iOS9…