he is not asking about monthly transfer, but using an affidavit from his embassy. And as he is from Italy, if they ever did it, they probably still are. Danish Embassy still doing them. Only a few stopped. If you have that, you don't need either monthly transfers or a lump sum.
my experience with them was very positive. But yes, they will look for reasons why the applicant will travel back to Thailand. Being your girlfriend and you covering the trip doesn't cut any ice. They want to see her connections to Thailand. Reasons why she won't just go there and try to stay there. Job. Kids in school. Owning a house. Etc. If married it's much easier though.
VFS global offers several add-on services. For example documentation and filling out forms. Go look on the website. You are going to apply through there anyway.
there is absolutely nothing stopping you from entering from a different country than where the visa was issued. You could have an itinerary through multiple countries. But they require you to be present in the country you apply in.