As a Captain Jack Sparrow myself I have to say that the Spaniard's outfit is mostly base pieces that have been embellished with alot of gold. The frock coat is simply a blue frock coat with lots of gold fringe. The shirt is a standard shirt but with lots of lace at the cuffs and the neck area. I would start off getting the basic pieces such as a) waistcoa,t b)shirt, c) frock coat, d) breeches, and e)boots. Once you get the base of the costume down then you can start with the OCD details. Start looking for the gold fringe, buttons, etc. The hat looks like a common musketeer hat with lots of feathers.
You have to remember that Penny Rose loves to use various non-garmet materials for her costumes so you have to think out of the box. If your going for 100% screen accuracy you will drive yourself insane. You can get "close as possible" and still be recognized as The Spaniard.
The baldric is intense and really cool. The baldric buckle is something you will either have to commission someone or make it yourself. That buckle has alot of detail.
My steps for Jack Sparrow back in 2005 were as follows:
1. Collect as many HI RES pictures and screengrabs from Bluray as possible.
2. Study the basic clothes pieces without worrying about the glitter and glamor stuff as stated above.
3. Start looking for the accessories such as baldric, sword, etc.
4. Hunt for the closest possible materials for the glitter and glamor trim, buttons etc.
Use your thread on RPF to show progress, solicit input, and other people can search for things as well. With Pirates of the Caribbean 5 - Dead Men Tell No Tales starting to film in February I will e on the hunt for new Captain Jack Sparrow parts (if his costume changes which some of us are predicting might happen) I will be on the look out for things for you.
Also check out Etsy for costume makers that have already made base costume items. I found alot of parts there for Angelica Teach.