First of all, the people inside are your relatives! Obviously, they left a deep impression on you. Then there is the place where you dream. A bunch of these temples are usually near home. It's still on the side.
You dreamed of a temple that didn't exist, because maybe you went to a similar place when you were a child! Now that place is very vague, the temple in your dream just replaces the place you have been.
Dreaming about your cousin becoming a monk or doing something is your opinion and idea about your cousin. Becoming a monk just changed your thoughts about her into a dream. You should be before or near 15, 16 years old.
Later, you dreamed that your mother worshipped God or something, because before Tomb-Sweeping Day came, you thought about what Tomb-Sweeping Day would do.
Obviously, your mother and other relatives are paying homage to your dead relatives!