Add ajax to a masonry isotope filter gallery with infinite scroll

I have a tumblr like image (and video) gallery built in MODx CMS and handled by Isotope to filter by 3 types of items. There is already a few hundred items so the page takes ages to load, which is why i need to have the page only load a few items first (AJAX?), then load more when you get to the bottom of the page like an infinite scroll. However the filtering functions need to work too. Also, the order of the items is defined by a date variable input at the CMS level which outputs the HTML items in the right order and needs to be kept. So to summarise: hundreds of items in a masonry layout with isotope filters that need to be kept in order but loaded progressively with an infinite scroll. There is currently code in place for the scroll and filtering but they conflict, and the page still loads every item before anything happens. If you are interested in the project please start your proposal with the word MFQP so i know you have read this entire description! Thank you.