Hummingbird & Gtmetrix result

Hi there - I recently setup a basic one page site and I have installed both Smush and Hummingbird in hope to increase my speed results and whilst a large majority of items have improved... there are some that have not.

First of all, as of today I can't even run a test... I get the error:
"The performance test didn't return any results. This probably means you're on a local website (which we can't scan) or something went wrong trying to access WPMU DEV. Try again and if this error continues to appear please open a ticket with our support heroes"

Second of all and what i'm most concerned about are the results that Gtmetrix are returning which I really hope you can help with.

I'm getting grade F for "Inline small Javascript", grade F for Defer parsing of Javascript, grade D for Inline small CSS and although not major, only grade B for Minify Javascript.

Please could you help me to improve these and ideally without having to upgrade?