Can someone explain some things about pf2 Witch and familiars to me?

1.
>Your familiar gains two additional familiar abilities: one of these is a unique ability based on your patron and is always selected, and the other is an additional familiar ability that can be selected daily as normal.
Does your familiar have two 'normal' abilities and two extra abilities (one from the patron and one regular; 2+1+1) or do you need to replace one of the two regular ability slots with a permanent patron ability?

2. Can the familiar sit on your shoulder all the time? I assume so, since it's tiny, but do the Ride rules apply to it? Does that mean I need to spend one action to stop it falling off (every round I have only 2 actions), and it would only get one action when I command it? Only he is penalized? Does it matter if the witch is small or medium?
Or is it just something GMs wave off?