1. Yes.
2. Yes, but this means you would need multiple images for those rooms or overlays of some sort.
3. Yes. Think of it this way. Can a blind player play the game?
4. The secret to a good text adventure is to anticipate anything that a player might try and allow for it. The example in 'Who Kdnapped Mothe Goose' may have been an oversight.
5. It does. Perhaps 90% or more of the coding will be related to point 4, i.e. actions and responses that don't lead to the ultimate solution of the game. A lot of the player's time will be spent exploring and trying things. The size is up to you. I know that at least three of the games will be quite large, but a short, punchy game can capture the player's interest enough for them to rate it highly. Maybe aim for a playing time of one to two hours.