Build an Online Store

Project to set up magento multi store (already started) on 1 main domain xceluk .com then 2 more domains xcelprint and xcelpromo under one install on the xceluk which has been already installed with the theme required (porto). The xcelpromo and print site will have the same theme to show a uniform apperance but a colour change to header and logo to show customer which part of the site they are on. The xceluk site will share the about us, contact us pages etc and share customers and logins detail across the sites. We have megamenu installed but needs setting up so the main header catergories are towards the domains with the drop downs showing catergoies within that site ideally so when the site structure is added in admin it shows this automaticly. We want the different sites to have a home page to show off the sites products i am sure this is a standard option in magento multi store anyway. We have a lot of work done and more work will be needed on these sites with some custom work in the future needed, so please price with this in mind.