Decks, Patios, Porches and Docks - converting a balcony to a deck

We have an existing 16' L (parallel to house) x 4' W (perpendicular to house) balcony off of the 1st floor of our house, which is supported by joists protruding from the basement. We want to convert the balcony to a 16' L x 12' W deck by adding four (4) 4" x 4" x 14' posts 12' from the house.

How should we join the existing 4' W balcony to the new posts, joists and rails that will extend 8' from the house, so that it is properly supported?

Can we "sister" the existing 2" x 8" joists to the new 2" x 8" joists or do we need to add posts less than 12' from the house?

Should we use two (2) lag bolts at the bottom of each 2" x 2" x 42" baluster to add strength to the railings?

Thanks in advance for your advise/expertise!!

I would run the new joists back 1' and nail into the old existing joists . then put a beam @ 4 feet out so its under the new and old overlap. and put your other beam @ 10 feet or 12 feet depending on design preferences. Theres a million ways to make a railing. Lags are going to be slower than some other ways that can be just as solid look around at some designs. Also i dont like balusters that are nailed .. screwed or lageed into the rim joist. It makes cleaning the deck a pain. I prefer to make 2x4 "frames" with 3 1/2 inch clearance at the bottom so it will pass code and still dirt leaves mud etc can be swept off the deck easy. Hope this helps--Josh