Rent a full body costume from any good costume shops in donwtown could also be an impressive option. They might not have Halloween them costume but you could probably find something suitable with a pinch of creativity using accessories.

Lugu Lake is located 2900 m above sea level, so I would not recommend to pass over the night in a tent.
Yunnan part of the lake is the more beautiful, you can find cheap room (around 50 RMB without lake view or 120 with) in Luoshui or Lige villages.
For guiding services, you can easily find minority guides from Lugu (Boumizu, Mosuozu), they own the best knowledge of the area.

Sure Yuanyanren estimations method are quite simple.
So the real question is how many are the unregistred foreigners (A motivated? distinction between Asian and Non-Asian figures could be appreciated), so that we should add them to the official figures (permanent tourists, black market working, fake students, etc) >?

Anyone had a recent experience in renting a car from a Kunming provider?
Is it cheaper to rent it using a Chinese driver or foreign driver?
What is the cheapest deposit for good service?
Anyone used zuche.com services?
I am planning to go to Fuxian lake in the coming weeks and drive by myself.

Just passed the test today.
'Fogdear' comprehensively described the requirements.

You need to arrive any Thursday morning at 9AM. On site, you make required photocopies of relevant document for 5 jiao each, pay medical check for 12 RMB, and exam fee for 60 RMB.

Then you are assigned a 2 hours range where you can pass the test (Mine was 9 to 11AM). You enter the exam room and they assign you a computer where you have 45 mins to answer the 100 questions (a camera is filming your face BTW). The 40 first are Right/Wrong, the 60 following are Multiple choice questions. (I needed 25 minutes to complete it). They are quite faithful to the study guide, though some English formulations were improved since my file version from a year ago. To me it appears that R/W questions were more difficult than the 60 others.

After succeeding the test, you pay a 10 RMB fee and they issue your Chinese driving Licence within a few minutes.

The whole process took me less than 2 hours.