If he had the time to do so, would Itachi ever consider learning how to play an instrument.

[[ Unless it could be of use to shinobi work (which, it can), then no.

But considering I just said instruments can be useful to shinobi work, the only example I can remember off the top of my head is genjutsu related, and Itachi does not need an extra item to perform genjutsu when his eyes work just fine.

He wouldn’t learn one for pleasure. ]]

Good point. I know itachji believes that telling Sasuke the truth would have somehow changed things. Do you agree? And if so how? That part never made a lot of sense. To me.

[[ Well, Itachi believed Sasuke could’ve changed the clan. But keep in mind… the kind of change Itachi wanted at 13 was for the clan to just stop fighting Danzo at every turn.

I think, Danzo included, having Sasuke aware of the plans, and Sasuke being able to do something like Itachi said… would’ve maybe only stalled the massacre, instead of avoiding it entirely. 

Danzo would’ve kept pushing and prodding the clan to get the reactions he wanted. ]]

Do you think the massacre could have been avoided if itachi just killed the higher ups like fugaku and tekka and them? Instead of killing everyone?

[[ No. Because that implies the massacre was the fault of Fugaku and the higherups.

Danzo wanted all of them dead. Danzo wanted every Uchiha dead since the beginning. So no, Itachi couldn’t have just killed the “instigators” and be done with it. This was Danzo’s order, and he wouldn’t be satisfied until every Uchiha was dead. ]]