Which word from this list has the highest letter count?The longest word that's possible to assemble from the combination specified is 'boldfacedness', which has 13 letters.
What is the highest scoring word in Scrabble with the above combination ?For 16 points in Scrabble, one can use 'birdfarm'.
How many words are possible to make using the combination of letters requested?From this page of words starting with 'b' that contain 'dfa', you have 11 combinations that are available.