1) Yes
2) No : Considering the item got a "prize" to be used as you damage yourserlf for it to proc for a completely luck based result, meaning that you can't really abuse it as you would with a remote combo. Also if you don't play it carefully it can troll you.
3)No
4)Yes : seems good to bring shops back in the game. (maybe make it like a choosable option in the mod menu ?)
5) Considering people may not collect ressources for the shop whith a strong build, the items of the pool may not be game changing but little boost, so yeah damage above all.

Edit: Partisan, Yes the tracker works with Afterbirth no worries.

Thanks for the answer sillypears, i understand my question wasn't so clear. 

To clarify i may ask it like this, "to make a run valid on the leaderboard" :
1) Is an item tracker mandatory ?
2) Is a timer Mandatory ?
3) Can a run record on local recording will do or is it mandatory to done it live on a broadcast platform ?

I understand those questions may seems dumb/obvious but i can't find the answer anywhere so ...

Hi everyone,

Is an Item Tracker mandatory to make a run valid ?
Also, what exactly is mandatory ?

Thanks in advance