Yes, the version on iTunes is an epub. But they are not happy with the links to Amazon so I will have to remove them and put it back up. That will take a day or two, sorry.
A pdf of the full book I'm not sure about yet, should I be concerned about copying? I'm new to authoring.
DISCLAIMER: the following is my personal belief, and I don't have more than a few anecdotes to back it up.
You shouldn't be concerned about copying no matter the format. Almost anyone who gets a copy of your book illegally is someone who would not have read your book at all if he couldn't have gotten it for free. And with these people, you are better of if they do get it; they may share it with someone who will become a customer, or they themselves may become customers in the future, when they learn that they like what you do and/or their purchasing habits change.
Gumroad has a feature called PDF stamping [1] that puts the buyer's email address on the PDF. It's not perfect security, anyone who wants to ignore your copy rights probably will, but it might deter unthoughtful sharing.
Also consider a team/company license priced at some multiple (15x?) that will allow a manager or lead to buy your book for their company/team without having to worry about violating copyrights or managing buying the book for every employee.
Yes, I did see leanpub and liked it, but they didn't support sphinx, which is what I knew at the time. Didn't know that they took complete .epub will put that on my list.
I'm from Indonesia. A lot of countries are excluded from getting paid contents on iBook (e.g. India, Malaysia, Singapore, Hong Kong, Korea, UAE, etc): https://support.apple.com/en-us/HT204411
Yes Calibre can read .epub, and there is a decent extension for Firefox I've seen.
However, I'm not yet making the epub available. The book still needs a lot of work. When it gets closer to completion, I will probably will make standalone files available.