I just realized you can access "Analysis" in daily games!

It doesn't give any hints or scores, but it allows you to "play out the game" several steps ahead on a board just like a physical board, and will tell you if a move is a checkmate. I find it very helpful because it is hard to play the game in my head.

Yes my friend, this is the whole point of daily chess! 

Yes indeed. I will also mention that you can use the opening explorer as well, just in case you didn't know. 

Not at all! Look at this, taken from this support article

• Books - You may consult chess books, lessons, or videos to search for a good move. These resources do not involve an engine that finds an answer for you, so are okay for Daily games!
• Opening databases - You may look at opening databases, or game records to find a good move. You may NOT use any of these that also use an engine to evaluate the best moves! 
• The in-game self-analysis tool - You may use the self analysis tool to look at possible moves, and to set conditional moves. This is only available in Daily games! 

Daily chess attempts to mimic correspondence chess, where, unlike OTB(live) chess, it was acceptable to use an analysis board and opening books. 

There are clubs you can join where the players agree not to play with an opening book or with an analysis board, and it would be bad etiquette to do that there.  But unless it is explicitly stated, use it as much as you can. 

As long as you don't use a computer/chess engine to calculate moves, or consult with another human about the game, for daily games you can consult other, passive, resources such as books, articles, online databases, opening explorers, etc.  However, for live games it is illegal to consult or employ any external aid or resource for assistance with a game in progress.