Custom Programmed Wordpress page

custom pages to be programmed into my Wordpress site. Both will use SAME custom templated format - just very slight differences in Pages. I have design mockup w/instruction, also have recipe wordpress plug in to be utilized for recipe archives on the FOOD page. Also need help with functionality of archives, want by category not by publish date. And "RECENTLY ADDED" sections need to link to archived related articles. Easy change out of photos and content, as it will be changed twice a week by an employee of company so want easy change out of info (XML?? - is that what I need?) Would like written instructions for my inhouse site maintenance person OR CLEAN CODE EASILY FOUND IN BACKEND so we will be familiar with what was done, and functionality (for me as owner and inhouse wordpress person) More work in future if return product is satisfactory.