13w USD is about 1m HKD. Tax is 8% for first level (300k HKD?) and 15 - 17% for next. So you probably get average 11% tax. Will you work in IB? Bonus could add a lot to the base

Mid level house in HK island is about 1w HKD/sqft. 红磡 is on KL. House there are sold for about 4000 - 9000 HKD/sqft. This is construction area. Living area is about 70 - 80%. Mortgage is NOT fixed. But interest is only ~2% now.

The other significant cost besides house is children education. Be ready to pay 100k HKD per year per child for international school.

All others are cheap.

Big env is way worse than US. Food, shopping and vacation choices are very good. You also save big on tax. You will pay SS tax, medicare and state tax. No sales tax. very little property tax if you own. Your first 87k USD is tax free from Uncle Sam. Also the tax you paid in HK can be counted as credit for US tax.