Yes, a wireless n adapter is backwards compatible with wireless g. Check the box you are buying and it will tell you if it is compatible with which wireless ranges.
Yes.
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 4 words with the pattern ---NLAN-. That is, eight letter words with 4th letter N and 5th letter L and 6th letter A and 7th letter N. In alphabetical order, they are: cornland downland mainland townland
According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 1 words with the pattern F-NLAN--. That is, eight letter words with 1st letter F and 3rd letter N and 4th letter L and 5th letter A and 6th letter N. In alphabetical order, they are: fenlands