Buy the gold chocolate coins and use them for a treasure hunt. Hide them throughout the house or the yard. Basically, let the kids hunt for their own goodie bags. You can get inexpensive spyglass telescopes at the discount stores or on line at places like Oriental Trading. If you want it to be totally "fair", give each child a fake pirate name (Google real pirates and adapt as necessary, perhaps including the child's real name), and label the little bags of coins with that pirate name. They can work cooperatively. You can have a blind hunt, or you can use written clues or a treasure map. We always did these with our son and the kids worked in small teams to find everything. They only went to the hiding places on their list of clues, so everyone got something.
Buy eye patches at the party store. You can guy those cheap kerchiefs with a fake earring hanging on it. I'm sure there's a whole pirate section there. Find a photo you like and have the store make the pirate cake with that image - they probably already have something you can use. Disney themes are in the bakery selection books all the time.
I would only do "Pin the X on the map" if you have 7 or fewer kids. Otherwise there's a whole lot of standing around for all but the blindfolded kid.
Google "Pirate Party Games" and you'll see some really cute ideas for "walk the plank" (board between 2 barrels or buckets), cannonball toss (use black water balloons), ring/hook toss (use rings on those fake hooks a la Captain Hook), etc. If you have a large group, half the kids can do one game while the other half does another, then they switch. Here's what I found - a bunch of nice photos. I'd spend more time on this than on making the cake yourself - the kids just won't appreciate the baking effort and they will appreciate the unique games.
I'd put a couple of pirate balloons on the mailbox or a pirate-themed poster on the door - not expensive, and sets the tone upon arrivals.
https://www.google.com/search?q=pirate+party+games&cl...
Have fun!