Website for estate agency

Hello,

I am launching and estate agent company and I want to have the website made. At the moment the designer is creating a design and will be finished very soon.

The type of website will be very similar to both of these:
https://www.marshandparsons.co.uk/
https://wetherell.co.uk/

It will definitely be a lot less content than these though as we have just started the business.

My questions to ask you :
1. How would you charge a project like this? Per page depending on how much content there is?
2. How would you design this website? We are going to be uploading property and property descriptions regularly and shouldn't require a developer to do this. Something that is easy to update
3. How long do you think it will take to complete?
4. Will it be phone compatible also? We need the website on the phone to look good also