I'm not sure, but:
1. I don't believe you can have more than 12 preset's of your own, but I'm sure you can have more than 12 of downloaded presets (Not sure, I'd let someone else post afterwards).
2. I do believe so, go on FeralHeart > My_Presets > find the file number and file the exported file. Right click it and press 'Rename'. If it goes wrong, I would just re-name it to its former one.
As I said, I am not sure, perhaps waiting for another answer would be a good idea.