Congrats on the new boat. The previous posters have offered some very good advice. I think it is especially advisable to sail with your friend and stay out of heavy winds until you get more comfortable with your boat which includes righting it.
There is a H16 parts guide on line at
http://2010.archive.hobiecat.com/suppor ... _14-16.pdfThe easiest place to pick up miscellaneous hardware such as pins, shackles etc. is at a local Hobie dealer. If you don't have a dealer nearby there are quite a few dealers that have online stores. Several that I have dealt with are www/murrays.com,
http://www.saltydog.com,
http://www.backyardboats.com. I have gotten excellent service from all of them. I especially like Backyard Boats. They have Hobie parts guides on their site and Its easy to find parts on their site using the Hobie part number. I think everything you are looking for is available on line. You will find that much hardware is really generic to all sailboats but if you order through a Hobie dealer using a Hobie part number you don't have to figure out what size you need.
I would not hesitate on replacing any rivets that are loose or missing. You need to. Just make sure to use stainless steel rivets not aluminum ones.
And yeah. Knowing the right terminology will make things easier. You are more likely to get the right part the first time.
Good luck. The fun only gets better.
Dave W
Tampa, FL