I like to do this job.
I'll make your site using most popular CMS platform called "wordpress", as you mentioned you would like to modify it in future, so you could od it easily even by yourself, and above of all it's very easy to do or maintain SEO.
I have many paid themes and plugins that i could use to make your site great.
I'll install and configure SEO, security, and cache plugins that make your site awesome.
I'll use advance technologies like, PHP, MySqli, HTML5, CSS3, Jquery, JSON, Ajax, and Bootstrap, as per required.
I'll give you 2 weeks free support in regards each project we'll do as you mentioned you need long term developer
so let start discussion and start project, and thank you for reading