Does anybody know if the Abilities that are tied to keyblades are active as long as it's one of the three equipped, or do you have to actively be using it? 

 I'm mostly referencing the Favorite Deputies Lucky Strike, I want the bonus to item drops, but I don't want to wield the Favorite Deputy (I personally prefer Ever After or Wheel of Fate for fights.)

Unfortunately, you have to have that Keyblade in hand for the abilities to work. There is a Lucky Ring in the game if you'd be okay just having one Lucky Strike equipped. My suggestion would be to use Favorite Deputy while you need it and make sure your team members are turned to Hands Off mode so that they don't skew your drop rate

And if you're synthesis hunting, here's a guide for it

https://gamefaqs.gamespot.com/xboxone/719078-kingdom-hearts-iii/faqs/76888

Thank you!  I got the Lucky Ring from the Postcard drop off.  Do you know if it is like the Orichalcum + and will only drop once? or is there a chance at getting multiple?

 

It only drops once, unfortunately but the normal drop rate is surprisingly high. With Favorite Deputy and the Lucky Ring, you'll get plenty materials