How do we protect our IP during pre-launch?

Spell everything out clearly in a contract or non-disclosure agreement - state that you are the owners of the IP, the people testing your software are doing just that, that they have no rights to the IP, and that they are being paid for their services only, which is the software testing and reporting to you on its operations, defects, deficiencies, whatever you actually hired them to do. Lawsuits are replete with parties who "thought" their "contract" with another party was as they "saw it" whereas the other party thought the contract was as "they saw it" - if you specifically make clear what the contract truly is, you will probably avoid contractual disputes including your rights to your IP.

The best way to protect IP before launch is to file provisional patent applications. By doing that, you can lock the priority date for your invention. Also, since you do not have to give exact claims in the provisional patent application, having a broad and strong provisional patent application would help you draft good claims during the actual patent application.