OK....it sounds like all is well with your tree, except the leaves turning yellow. Of course it is possible you are just loosing a few leaves, they do that. Is there any new growth? It does seem like you maybe overwatering it. There is a simple way to test for water need. Take a piece of chop stick and place in the soil halfway between the trunk and the outside edge of the pot. Everyday take the stick out and feel the end, if its wet (damp) its OK and no water is needed. Replace the chopstick. If its dry you waited a little to long, it should be turning dry when you water. You can kill a tree quicker by overwatering than by underwatering, although neither is very good for the health of the tree. I know this from experience!!! I am a novice who has been there... done that.... saved a few....learned from the others (I hope).
In general I would think that every other day maybe to often. As for the misting, it will do no harm, but to be useful you need to do it several times each day....a humidifier is better.