Self-Referential Puzzles

This set is a bit longer than usual. I have compiled several puzzles having a unique quality - the answers affect the answers. For example, if asked: only the spelled number "Four" could be an answer, since it's the only number with the same number of letters as the number ("Five" has 4 letters, "Three" has 5 letters, etc.) Of course "0" would also be a valid answer, since it doesn't include letters.


Spelling puzzles From Philippe Fondanaiche:
Digit Puzzles (fill the blanks with digits 0-9, or possibly multi-digit numbers): From Philippe Fondanaiche:
Self-Referential Numbers
If you find other puzzles of this sort, feel free to submit them. I'll add them when I can.

Source: Unless noted, these are original.


Solution
Mail to Ken