I believe this project could be done relatively quickly.
I bid pretty low so I could receive a rating quickly. I am not yet established on this site as a freelancer and would love to change this.
The extra page youd like built shouldnt take long, though if not already chosen, prepare to create copy(text) and/or images for this page. As a separate note, not included in the bid, I do offer graphic editing and cartooning. Creating images, considering the type of page needed, shouldnt take long.
Most of your other changes seem to be quick css updates(or load order).
For the filters showing first and wrong font being displayed, this should be somewhat painless to fix as well.
As far as your site loading slowly, Id have to see it, which I couldnt find the link in the description. DO NOT ADD A PLUGIN. Adding more stuff to load could potentially increase the time loading or may cause an unexpected change. Fixing the problem with the filters and the wrong order showing may fix this. If not, we would start with image optimization, dependancy loading, unneeded hidden content, external code calls. Ideally, we could reduce what is needed on a page to page basis and fir pages that still have a longer load, we would likely try to load the portions in order of top-to-bottom, but will prevent the page from waiting on data to load and would try to reserve some apace on the longer load portions with fancy loading notes for the user.
As another note, css filters are not my favorite tool. In general, we make a goal in web development to not use tools like this because of its cross-browser compatibility. Css filters are not always prpperly working in internet explorer, though edge kinda supports them(and you definitely need prefixes to increase the compatibility). Id try to convince you to allow an update for the filters to another approach. I have a few options here, but cannot make any until I see what im working with.
There is a slight chance by "filters" you meant search filters. In that situation, we actually just saved a step.
Included in my bid is a level of QA that includes cross browser compatibility, grammar checks, consistency, and status code checks.
Let me know if you have any questions.