Using wireframes for UI design and front-end development

Using wireframes for UI design and front-end development

I created this wireframe/sketch to have a UI designer bring it to life,
however I have some questions about the wireframe and grid system:
wireframe: http://ho.io/main_page_wireframe
sketch: http://ho.io/main_page
1) Would I be able to approach a UI designer with the wireframe/sketch above?
2) During the UI design (feel and look), should we pay attention to the
fluid grid system or is it relevant only during the development?
3) Would it be more consistent if my UI designer is the front-end dev as
well or not necessarily?
4) What are the concerns that I should have between wireframe -> UI design
-> front-end development?
Thank you.