Weather of Yunnan

It gets chilly but won't snow/rain as it's dry season. you'll be going up by cable car so no big efforts required. LJ's at 2,400 m altitude so the risk of mountain sickness is of 20%, make sure you all drink plenty of water and you'll be fine.

I'd stay away from LJ which is WAY TOO touristic, look at Shuhe or even baisha to have a quiet place to visit.
In Shuhe there's a great boutique hotel called bivou and if it's out of your budget, check out the hotel next to the french wine bar Chine~Chine in Baisha, they're very affordable, clean and nice.