Hi, Jfgomes! Welcome to the raw side!
To answer your specific question - "holistic" food sources are just as much healthier for your cats as they are for you. However, they are not necessary for a successful raw diet.
Some tips that might help your transition efforts:
First, stop free-feeding dry. Get your cats accustomed to eating on a schedule.
Next, put some raw meat cut into very small chunks on a plate right next to their dry food while they're eating for a few days. Just enough meat so they can smell it while they're eating and begin to associate raw with "food".
Then drop just a couple of kibbles on top of the raw meat and offer it before the kibble for a few days to see if they'll try it. If not, throw away the kibble pieces and put the dry food next to the raw for a few more days.
You could also try sprinkling freeze-dried meat treats on the raw food. Stella and Chewy's makes some, as does Whole Life and many others (I use, and LOVE, Whole Life's Freeze-Dried Chicken!). Cats often find these treats irresistible, and they sorta melt onto the raw food and can't be licked off without giving the cat a taste of the raw.
As your cats learn to eat raw and gain chewing expertise and strength, you can slowly increase the size and toughness of the meat you are feeding (chicken is very easy to slice through, as is pork - turkey and beef are more difficult) and, eventually, start offering bone-in meals that contain small, easy to chew bones such as chickens ribs and wingtips; all the while reducing the amount of dry food offered. When the ratio of raw to dry reaches the 50/50 point, you can also start offering very small pieces of liver and kidney.
Here's an article you might find helpful: How to Transition Your Cat to a Raw Diet
Though this refers to transitioning from dry to wet, there are some more ideas in this article that might be useful: Transitioning Dry Food Addicts to Canned
Sometimes you can move cats right from dry to raw. If you can't, though, switching them to wet first would definitely be a good option.
Good luck, and let us know how it goes!