Help Finish a Wordpress Website Project

Hi, I'm currently in the middle of a wordpress website project. This is the old site - [login to view URL] This is the new site (in development) - [login to view URL] 1) Fix the 500 internal error that's occurring (if you refresh the page a few time it eventually loads). 2) Make sure all the onpage SEO for the new site matches the old site. The client doesn't want to lose any of his rankings so we need to make sure all the title tags, header tags, meta descriptions, image tags, links throughout the site etc are all the same. 3) The previous developer didn't use a child theme. Would like to have this implemented so we can update the theme without losing all the design/breaking the site. 4) If possible I'm hoping to find someone who can help select free stock images that we can use throughout the site (all the header images for each page should be unique, and the blog posts could use some custom images that match the topics, etc) - this one isn't required, but it would be great if we could achieve this. 5) Any other issues you currently see. Open to additional recommendations. Basically this project needs some refining and i'd love to find someone capable of improving everything and going through some revisions (as needed) with the client. Please send over recent websites you've worked on thank you. I have website projects available all the time if this one goes well.