For your wife's baking business, would recommend a card that would maximize grocery benefits- not only at your regular grocery store types (Safeway/Kroger) but also at the Smart and Final type stores as well.
So you are looking at either the:
- Amex Hilton Surpass (6x points on grocery), also comes with bonus on gas and restaurant spend, and a free weekend night cert that you could use for Disney trips.
- AAdvantage MileUp card (2 AA miles per $ at grocery)
- BlueCash Amex (6% cash back on up to $6k per year)
You could always make your wife an Authorized user on a card and know that all spending on that specific card # is for her business?
For everyday, non bonus category spend - BoA cash back or Citi Double Cash would likely get you $ to spend at Disney racked up alot quicker than the Disney Visa, which rewards just a few categories and the reward currency is only valid via Disney.
Also, if you are Costco members and your wife's business needs could be met by buying there.... up to 4% rewards for spending on their visa + exec membership. Not to mention gas savings on pump price plus 4% cash back.
Are you getting much value out of the Platinum card? Hefty annual fee that wipes out alot of the value you create via points if you are not using the card benefits alot.
I would try and trim some of the "fat" on annual fees to help keep your net rewards earning at a higher level.