Re: IF I SEND BTC TO A FRIEND/FAMILY, DOES IT MEAN THEY CAN KNOW MY WALLET BALANCE?
If I transfer BTC to a friend/family, they now know my wallet address, correct? Does this mean they can see all the transactions I have done from that wallet? It seems like wallet information is public except for identity, but that would be forfeited once I make a transfer, right?
Yes they will know your wallet address since you are the sender but if the receiver doesn't know anything crypto related then he will not know your address 
.Since there is a thing called "blockchain" which acts as an online ledger then they will see all of your transactions unless you will use mixers.
That is the reason why Bitcoin is pseudo-anonymous because they can still track the owner.
If you don't want to forfeit and want to make your identity to be private, just use another address to send money to them though they can still track you if they will try to track that address' transaction. Maybe just use mixers so that you can keep yourself private whenever you will send BTC to your family or friends.