Neither. You need to hire a business analyst first who will define what goes into the app and breaks it down to a point where it's granular in terms of workflow, features, functionalities, integrations, algorithms, etc. This is what sets a foundation on which the wireframes and design is drawn up on. Secondly, UX is not a standalone function. It's what a UX designer and the lead developer together define in an app, in an ideal situation. I would have the two working together, but only after you nail down the Functional Specifications with a business analyst.

Incidentally, I just wrote a column addressing just this question. You can read it in full here: http://www.inc.com/rahul-varshneya/how-to-validate-a-business-idea-ask-these-5-questions.html

The standard procedure is to sign a mutual non-disclosure agreement with whoever you are disclosing your idea to, before you hire the firm. Once your product is built or is in the process, you have the option to patent or copyright it. Here's my article that gives the complete details on both: http://thenextweb.com/insider/2015/05/07/does-your-mobile-app-need-a-patent/

If you're offering him the 5%, you need to legalize it by forming a company and having it put into the documents. Your CPA or lawyers will guide you through the process.

A prototype will not get you an investor, to be honest. This is just a fallacy. If you can fund the prototype, launch it in the market, get some traction from users. See if your mobile app resonates with your users. You need to track whether your app is able to retain those users so that they keep coming back to it. If you have a good amount of retention with the first few set of users (100 or 1,000), that's a good pitch to take to an investor. Investors are not looking at ideas, they're looking at businesses that can get, retain and engage a customer.

Here's an article that I wrote recently for Entrepreneur magazine on ASO which should answer your query. How to Use App Store Optimization to Get Attention http://www.entrepreneur.com/article/227905

Better An Existing Problem Many startups were not the first in their domains. Take Google for instance. Many popular search engines existed – Altavista, Yahoo, etc – and we never thought we would move away from all of them at once. Adapt Existing Solutions To Problems In Your Country Many ventures exist which essentially do the same thing, but with localization. For example, SnapDeal is a Groupon clone in India with localized content and features. Google’s clone Baidu is hugely successful in China. And Singapore has its very own Pinterest clone called Singterest. Apply Existing Solutions To Your Industry Think Linkedin. Social networking concept adapted to the business industry. Think Airbnb. A popular Hotel search and booking concept adapted to the Bed and Breakfast industry. Seek And Address Existing Pain Points Every business vertical has issues that will range from areas in marketing, customer acquisition, customer service, sales, operations and others. Chalk out the industries that you identify best with and would be passionate about working within. Then, speak to a wide range of professionals from that industry to understand what problems they are facing in their jobs. Write all the information down in an excel sheet and then begin to narrow down into the most common problems faced by people and choose the area that excites you enough (marketing, sales, operations, etc). There you go. You now have a list of problems that require a solution.

I agree with Adii. It's not about which country should you outsource to, but about outsourcing itself. When you are bootstrapping to launch your venture, pool in all your funds, keep the costs low and go with an outsourced provider that understands your requirements best. I understand the predicament that you may have with regards to outsourcing, but the most important thing for you at this moment is to get your product out there. Once you have a Beta going, maybe go in for funding, scale it up and hire a team who can then carry it on from there. Some of the most famous products today were outsourced in their initial days – Alibaba, Fab.com (to an Indian company), Digg, Skype. And these are only a drop in the ocean of such examples.