Yoga pants, jeans and sleeveless

We are visiting Beijing, Zhangjiajie, and Hong Kong during our trip. Are yoga pants acceptable during tourism activities such as visiting the Great Wall, touring in Zhangjiajie, and other leisure activities?

Also, separately, are dark jeans acceptable to wear to dinner in Beijing and Hong Kong for both me and my husband? Or should I plan to wear a dress? He will wear long sleeve collared dress shirts.

And finally, are sleeveless tops or dresses acceptable?

Any other tips or suggestions? :)

Thank you!