I have an M&P 9 with no locks or safeties. IMO, the internal lock is stupid. You need a "key" to operate it. I have a trigger lock on mine at home and it takes 2 seconds to take off with no tools. The manual safety is a trickier question. Some like it, some don't. Some are used to 1911s and feel naked without a manual safety, some believe in the DAO concept and heavier trigger and feel no need for the safety. Get what you prefer as far as the manual safety but I would skip the internal lock.
Just my opinion, can't go wrong with the M&P though! Congrats!