The years I had guineas on my place, I had no ticks and very few chiggers. I'd get them again, but the neighbors don't much care for all the noise, plus the birds need at least ten acres to roam in and I don't have anywhere near that much area.
If you do have them and find a new nest, recommend you put some of the eggs under a good broody hen. They take a day or two longer to hatch than chickens do, but she will be a good mama to them when they hatch, whereas guinea hens drag their newly hatched babies all over through all sorts of stuff including the wet grass in the early morning. And if a baby lags behind and hollers for its mama, she doesn't bother to go back and get it. Also they will lay eggs in an enclosure, but they won't set them when they are confined, so the eggs go to waste unless you care to use an incubator. And often all the females will lay on the same nest and you'll eventually find one hen sitting on a HUGE pile of eggs!
Don't expect even hand-raised keets to become pets. They are simply too wild to tame.