Software product development for offline proven concept

We are a startup which was started a year back to understand the need of the financial distribution of corporate structured trade/off balance sheet requirement. We are based in Hong Kong and the product gap exists as on date. Till now it is self funded. We now want to build
a) MVP and launch it is in the market
b) Keep the software code in-house

In this scenario, our query is:
a) How do we optimize the cost of development while keeping it scalable
b) How do we keep the rights on the code
c) As novices with no software background, how do we set up a benchmark for evaluation of the best product?

Thanks for reverting on the query. Offline proven concept means hypothesis testing and execution on normal delivery models like origination through client calls and distribution through normal banking/alternate liquidity channels through emails and phone calls. Though this is customizable but it is not scalable and the deal sizes become a constraint. We are working on providing off balance sheet financing products to either buyer/trader or supplier of goods.
We are looking at a Web Browser Model - wherein the information exchange can be real time. The primary issue will be the authentication of the request emanating from each of the client port (who will be a corporate in nature and in a emerging market) and the distribution will be in the specific liquidity port (institutions in the developed market) with process flow in between to synthesize the information and to structure the trade flows. On both the ends we may have to authenticate (which I don't know needs a desktop software or not). We are also looking at launching part process flow like origination etc on mobiles before having a fully integrated system. At a product level, given the liquidity constraints, we are trying to give financial product solutions to the SME's and the corporates by bridging the credit appetite and the liquidity with/without banks involvement.