Hi,
I have gone through your doc and post.
As per my understanding you want to improve some function of your opencart site,need to improve searching of back and front-end,need to create feature to generate reports in back-end and then export in .csv or in .pdf also other tasks like courier integration,payment integration etc.
I have expertise in opencart and want to assure you for quality work.
Looking forward to hear from you.
Thanks