Yes, Chinese New Year. Expect prices in Chiang Mai to shoot up over new year, as it is now a hot destination for Chinese tourists. Make sure have access to enough cash/bank card flexibility. You can probably check hotel prices for that period already. I expect demand will be high and availability to reduce as the holiday approaches.

I don't have your answer, but here are some things you may wish to consider.
When checking freight costs, an important consideration is weight per item. That is, a box of over 20kg may be considered more than one person can lift unaided, and may have additional handling charges applied. It may be cheaper to send two lighter boxes.

If you can find a carrier that will ship it as personal effects, you should not attract customs duty. Some removals companies in UK will handle small home moves, especially for students's personal effects, when returning home. It is possible that other carriers will do this. It might be worth checking Australian websites for companies that do this, and see if they have agents in China that will do a reciprocal service.
Be aware that a lot of couriers (like DHL) will charge you customs duty in your home country, and add a flat fee for handling the customs paperwork. This can add a lot.

I know this will probably get bumped to clasifieds, but so that it has a least a couple of hours on the front page...
There are many of us in Kunming who make stuff. I have started a Wechat group so that similar minded people can share what they are doing, sources of materials and tools, sources of advice, and just to show off what skills we have out there.
So far we are few but the skills we have a woodworking, metal working, basic upholstery, and baking. If you would like to join the group, please PM me with your Wechat ID or add my Wechat markinkunming, tell me what you can make and I will add you to the group.

A lot will have to do with where in Canada you de-plane.
I spent a while living in Alberta, and traveled west.

If you like wild country, Then if you get to Vancouver City (not Island) and drive north up the coast it is remote, wild and beautiful.
Vancouver Island is nice. Vancouver city harbor and the coastline path around the city is also nice to walk or cycle.
Forget Banff as overpriced and about as Canadian as mi xian.

Calgary is just a city, and during Stampede is overbooked and overpriced, but the Calgary Stampede is a kind of national icon.

Edmonton, famous for its shopping mall.

Waterton Glacier National Park, stunning in the summer when we went. Skiing in the winter.

Driving along the Trans-Canada highway. What can I say? Once you get passed Calgary (driving east) mile after mile of sod-all. If there is a tree it is on the map. Pretty much the same all the way through Saskatchewan. I never got further east.
However, I would like to visit Prince Edward Island. Pretty remote, but real natural beauty.

Guiyang has changed dramatically since I was there last, about 10 years ago. Travelling towards Guiyang, and even as close as Water-City, there is a lot of dramatic scenery. If you are travelling by road, the brown tourism road signs are also much more prevalent than they are in Yunnan. I am not sure if this means that there is more to see, but there is certainly much that is easier to find.