I'd say the most important thing would be deciding if you want to fully outsource implementation, or if you want to 'ramp up' your coding to do it yourself. Starting a biz is stressful enough that you might not actually want to be responsible for implementation along with sales, customer support, accounting, etc.

For the MVP I'd recommend building on a tech stack you know/want to learn, or can hire consultants for easily (hopefully without breaking the bank!). Once you've identified the stack, I'd look for someone that not only has a solid background in the stack, but can also document/explain the application, provide mentoring (if needed), etc. Definitely someone that will be around to update/modify the MVP based on customer feedback or at the very least able to help architect/vet any changes you make yourself.

Depending on whether you're building a SaaS style app, or something installed locally by each client, you will have other questions to answer regarding hosting, support, software upgrades, etc.

In short, implementation is often the 'easiest' part of the job. Knowing what you want to build, and how you want to build it can be the real problem :-P