wow. First let's start with the helmet. Check your helmet. see if it is still intact, no cracks in the white foam stuff. If it's okay, you don't need a new one.

the ride you want to attempt is long. You will really want padded shorts
and gloves are a necessary safety item. You can use the sunglasses
you already wear, and regular teeshirts or sports shirts on top.
You don't need hydration packs, but you will need a way to carry water.
There are bottles of water that sell in the store that fit in the bottle carriers on the bike if need be.

What are the pedals like on your bike? do you have to clip into them? if not
you don't need the special shoes.
I personally do not like most bike socks and have ridden almost 2000 miles this year just
wearing the socks I want to wear, so don't worry about the socks.
Pump? well, if you're always riding with someone who has one, you can get away without it.

and i hear trainers are selling on ebay! good luck