The gear shift is suffering from a worn "antivibration" set of bits inside the chrome part of the lever. A Chinese jigsaw puzzle....
see
https://www.pieces-fulvia.com/kit-mounting-rings-gearbox-lever-fulvia-serie-2-3-all-models.htmYou have to take the lever off to remedy.
Re handbrake there is an aperture in the drum and with a torch at the bottom of the brake assembly you should see a brass knurled adjuster "nut" with a strong brake shoe spring above it. The adjuster is operated on by a flat blade screw driver. To adjust, slacken the cable and wind up the adjust till the drum locks then back off (about6-8 clicks should have the drum free). If you have an air line good idea to blow the dust out of the drum (dont breath it in...). You may find there is no friction material left on the shoes in which case you need to withdraw the drum. A special socket is required that can be hired from the club.