@Benjamin *****
1. It has to be a local lawyer. And from the same province of the business.
2. Not a big firm
3. He/she is doing litigation too (not just consulting).
4. Consider a small business instead of a company. It keeps you below the radar. Personally I would choose to spend 500k for 5 years easy vip visa than this business visa based on investment.
5. To extend your business its always possible. It looks to me a real mistake to spend 3 million THB on business in a rental basis (as you are in the hands of the owner - he will up the rentals whenever he think you can pay). Start small and if you feel successful buy your own place and do the investment in your own property (real estate prices now are extremely cheap).
(*) I write it on behalf of 6 years experience running my own restaurant and bar.
Wish you luck.