Quick question about wheels.

Hey, just another new guy here! So, basically last year i brushed the dust off my old skates and found that rollerblading is still awesome. So, before winter came and skates went to hibernation, i saw that my wheels were in quite bad shape. So i decided i shall get some new ones. Since i don't know alot, i hope you guys could help me out a bit. I got K2 F.I.T 84 (something like that, from 2015 i think). Found these wheels - https://www.skatepro.fi/69-33549.htm

I mean, they should fit right? About hardness - current ones are 80A, new ones are 84A(?) - Are 84 softer/harder and do they make any BIG difference?

Also, If anyone got any good links for new wheels (with bearings), i would gladly look (From EU would be awesome).

Sorry, for the long post and any misspelled words (English isnt my native language, and also autocorrect).

Thanks!