They are both nice. I personally like the aqua. I would choose based on which color coordinates best with colors in your adjacent rooms, so you get some flow between areas. Also consider the flooring in the powder room.

They're on Houzz as a pro, Why don't you ask them? https://www.houzz.com/pro/studiomcgee/studio-mcgee

Talk to your local paint

Are you renting this place out, or is this a rental that you are residing in? In either case - imo, the enhancement that would make the most difference in the space would be a new vanity light, more updated, with more style. And if you are the tenant, you could possibly change out the current light (hire an electrician if your landlord won’t put it in for you), and keep the landlord’s fixture to return when you leave. As a tenant, I would not paint walls. That is really the landlord’s job. I would also absolutely not paint the vanity. That is the landlord’s property. If you are the landlord, I don’t think painting the vanity a bright, taste specific color will really help your cause. The existing vanity is nice enough, and it is a good neutral element in the space. And if you are the landlord - definitely no wallpaper - and especially no bright colored, very specific/personal taste oriented wallpaper. No one wants that in a rental. If you are the tenant - honestly, I would not bother with the wallpaper. You can bring in vibrant color with a shower curtain and/or towels, art, etc. If you are the landlord, please let the tenant choose and purchase their own shower curtain; it is not necessary for you to provide one. If this is an Airbnb - just a simple, white plastic liner, such as used in hotels. But if you are the tenant, and you feel you absolutely have to put up wallpaper - for an accent wall, the vanity wall is usually the best choice in most bathrooms; and imo it would also be the best choice in your bathroom.