1. One of my favorite song writers, from Scotland: Andy M. Stewart
2. Sorry, no.
3. No, I'm not. Yet? :p
4. The old folk musicians of Denmark have always (well, from we know from interviews with the ones that were about since we got out and interviewed them some fifty/fifty+ years back) used pop(ular) songs from revues and, later on, the radio - they weren't even written to a traditionally inspired tune! What do I want to say with this? Good question ;)
5. Well, depends on what you want with the song, but I don't think it's a necessity. Some of the contemporary Danish folk songs use words that are fairly modern, but the tunes are still hopsas, polkas, waltzes, polskas, and so on and forth.
6. Søren Korshøj, from Denmark, generally writes songs for either traditional melodies and contemporary ones with traditional 'rules'. Such as hopsas, schottisches, and so on. I think this is where I would probably set the limit. If one wrote a song for a tune which has next to none resemblance to anything known in any tradition, and called it a 'folk song'... well, I wouldn't agree with them ;)
7. Not right now, no :)