I was kind of wondering - for CNY 12k-16k per month - that equates roughly to CNY 400-600 per day.
I'm thinking you could stay in a 4-5 star hotel (or move from hotel to hotel) for that amount, negotiate a discount for long-term stay, and rack up frequent flyer miles and room upgrades. The Intercontinental hotel out on the edge of town, but next to scenic Lake Dianchi has enough restaurants to keep you busy for a month, before palate boredom sets in.
As you're here for business, the hotel is a sensational environment for business meetings. As a long-term guest - you MAY be able to negotiate freebies, heavy discounts, or other things.
As you'll be packing on the weight with sedentary hotel lifestyle - you can hit the hotel gym and pool gratis as guests.
Also - as long-term guests - I believe you're eligible (negotiable) for free buffet breakfasts, and whatever else you can negotiate - ESPECIALLY if you pre-pay (use a credit card, just in case they renege on the freebies).
The Hilton hotel recently (dunno for sure, haven't checked myself) opened about an hour away from town by the second (and in my personal opinion, significantly NICER) lake, Fuxian Lake. So, when you get tired of the Intercontinental, pop over to the Hilton for those "down" weeks, when you need to compile, analyze, etc the information you've gathered.
The Hilton is roughly 60-90 minutes from downtown Kunming (not including the time required to exit Kunming during rush hours).
Green Lake has a boutique hotel VERY close to the downtown area - but still in the Green Lake area - bit noisy and stinky because of heavy traffic during morning and afternoon rush hours - but aside from that - you'll have access to a plethora of restaurants and an open air farmer's market a few kilometers away.
One drawback - catching taxis around town is torture, so either learn how to use the online taxi apps (the concierges at the 5-star hotels can help with that) or get a private driver (recommended) with a car. The hotel MAY be able to provide recommendations for contract drivers with cars.
Get a COUPLE of referrals, in case your driver is an asshole (it happens).
So instead of going for the short-term rental - you MIGHT want to go the hotel/boutique hotel route - unless you love shopping for groceries and cooking at home.
Many restaurants near green lake MAY provide delivery service (for a fee - but you'll need someone to help you order if your language skills suck).
You also MAY want to opt for bi-lingual assistant for the duration of your time. The BEST students for this are the university Tourism students.
I've interviewed hundreds of students with various alleged English skills and the tourism students usually have (for Yunnan) spectacular English language communication skills. They may NOT be conversant in the specific lingos of specialized markets - but if you spend enough time with them - they can get up to speed remarkably quickly.
Good luck with your investment due diligence and beware frauds soliciting free gifts to "introduce" you to key government officials, contracts and other fraudulent corruption laced manure.