If I play Fizz to play Ride the Wind on him and move him to BF Abandoned Hall, can I give that Fizz +1 or not, since he wasn't at BF when the spell was played, only when it resolved and moved him?

No, you cannot give the Fizz, Trickster +1 [M] (Might) from the Abandoned Hall in this scenario.

The Reasoning

The ability of Abandoned Hall is a triggered ability that occurs when a spell is played. Triggered abilities are placed on the chain as soon as the spell is finalized (Rule 359.3). Because Fizz, Trickster's ability is what plays the spell from your trash, the following sequence occurs:

1. Fizz Enters Play: You play Fizz, Trickster. His "When you play me" ability triggers and is added to the chain.
2. Fizz's Ability Resolves: You choose Ride the Wind from your trash to play.
3. Spell Finalized: Ride the Wind is finalized. Because a spell has been played, the Abandoned Hall ability triggers and is added to the chain.
4. Chain State: The chain now contains the Abandoned Hall trigger.
5. Targeting: The Abandoned Hall trigger requires you to choose a unit you control at the Abandoned Hall. Because Fizz has not yet been moved by Ride the Wind (which is still pending on the chain), he is not yet at the battlefield and is not a legal target for the Hall's trigger.
6. Resolution: The Abandoned Hall trigger resolves. Since no eligible unit is present, you cannot grant the +1 [M]. Finally, Ride the Wind resolves, and you move Fizz to the Abandoned Hall.

This interpretation is consistent with RiftJudge FAQ #9723, which confirms that because the trigger condition occurs and is placed on the chain before the unit moves to the battlefield, the unit cannot be a valid target for the effect.