Whenever your lab do potty inside wipe that place with plain vineger so that the smell goes off, next step is, you need to set the place in your house where your lab go potty, put some clothes/news papers which had your pup urine smell (as what navjot said) on that place, take your pup to that place on every one hour and after his meal time and play time. You pup will learn to eliminate on these areas only. Dont worry labs are very clever and they learn quickly.
Another thing is dont ever allow your lab to bite, it is the very bad habbit, please dont encourage this. You should always be in alpha position, and your dog should always have some respect on you. My lab also behaves similar thing when he is 4 month old, I rolled news paper and hit strongly on ground whenever he start biting, thats scares him. If still bites I will just ignore him and put him alone. One of the worst punishment you can give your dog whenever he did something wrong is just ignoring him and not speaking with him.