I don't see where she was ever a cutting horse - ranch cutter maybe, but that ends up with different training than a show cutter. Did you get the full story on how a horse bred, raised and used on the same Florida ranch (according to the sale catalog) came to be at a sale in Michigan? Only seems odd to me she because would likely have commanded a decent price with less hauling costs at a sale further south.
If she's an ear pinner, I wouldn't blame that on cutting lines, I'd call it an overall undesirable attitude. Anyway, to answer your question, the best way to make her a family horse is to get rid of some of her fitness. Just do light work for 4-6 weeks and pack about 100lbs on (unless she's already fat). As with any horse, be sure to not let them get away with any bad behavior, but remember when you go to kick or jerk a cutter that they can move out from under you much faster than a plow horse.
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