1. Familiar is controlled like any other character of your party (clicking on its portrait), you can move it as allowed by standard rules (base speed is different, as well as stats and skills).
Currently familiars can only use skills (hide, jump, dash) and their special attacks (varying from familiars), but cannot interact with items or people other than attack them.
Imp familiar (from Warlock) is very powerful ; 12m base speed with 18m flight, plus piercing attack that can poison, on top of that invisibility as an action and AC 16 + 10 HP + resistance to all damage...
May even be more resilient than a tank character, especially since a warlock can resummon it at will... :p
I'm eargerly waiting for the ability to cast spells from the familiar (making it a remote controlled spell), since speaking through them looks pointless in game (Larian may have to buff the related Eldritch invocation to make it useful).
2. Only Wizard can learn spells from scrolls (right click > learn spell)