Not sure if flying should be omitted from the [0:] ability as it seems unnecessary since it's unblockable. Currently I have it there for flavor purposes.

It's a common convention to have the plus abilities of this sort to be optional in their targets so that they can be activated even when there aren't any legal targets for them. For example, see Jace, Cunning Castaway and Tamiyo, Field Researcher. My point is that I would change that +1 to "Whenever up to one target creature..." It's also notably that is very similar to aforementioned Jace as it has the exact same starting loyalty, mana cost, as well as a similar +1 loyalty ability. I would address that and change it in some manner to be more distinct by comparison.

Is there some particularly relevant reason as to why the draw on the first ability is optional?

The second ability has a weird redundancy where it becomes a creature with both flying and "can't be blocked", which renders the said flying wholly meaningless. It get that it makes sense from flavor sense for it to have flying it feels mechanically extremely awkward.

Some rules text typos:

"... to an opponent" should be followed by a comma in the first ability. "Faerie" and "Rogue" should be capitalized as they are creature types. The third ability should say "can't be blocked" in the same manner the second ability does. Loyalty activation costs of "0" aren't preceded by a "+" sign (for example, see Lolth, Spider Queen).

The second ability should btw specify that Pin becomes a "a 2/2 Faerie Rogue creature".