Are square moon signs enough to ruin otherwise good compatibilty?

No, I would just be watching and know that Scorpio is not comfortable revealing their emotions until they are positive that they trust the other person. So the Leo moon would need to understand that. And Leo is not really that comfortable telling all either about their emotions. Yes they can be the life of the party, but when there is no spotlight they generally do not like to expose their emotions either. So not do bad. Just do not ask each other all the time "How are you feeling?" You both will open up when you are both comfortable to open up to each other. Don't ask for commitment either as both signs take that very seriously, esp Scorpio. Don't talk about future plans such as marriage. In other words, don't rush the relationship in any way, shape, or form. Now your Mars are in what is called an opposition 180 degrees apart. The Scorpio Mars needs to be very very watchful of what hs said to the Taurus Mars. Both are very stubborn. This could mean some difficulty when there are arguments. Be sure not to have battles that are not worth a battle. Save it. When there is an argument the Scorpio Mars will really have to watch their words because Scorpio knows others weaknesses and when angered, let's them fly! Don't do that Scorpio Mars. And Taurus Mars can be extremely stubborn and you will not be able to change their mind when they have made a decision. That would be very difficult indeed. So save energy and only fight worthy battles. Be respectful of others emotions and you should be fine. Good luck and bless you both.