Our 6 year old pug has suddenly started peeing in the house and most recently peeing on our sons toys last evening.

He uncharacteristically bit him last week.

We are feeling uncomfortable about her being in the house now.

Can anyone offer ideas as to what might have caused her to start this behavior?

I would say it's time for a full health check by your vet.

Have is eyes been tested at all recently?
We had a dog years back who bit someone and it turned out he was actually partially blind in one eye. We are guessing he just saw a flash of movement and struck out not knowing it wad a person.

As for the urinating on toys, he may actually have a bladder problem, dogs usually try to be clean where possible so he perhaps thinks that by urinating on the toys it's better than going on the floor and in his own little mind he thinks it is OK.