Was sad to see mine go, but I only wanted them free range, and the foxes kept picking them off, wasn't fair. Persevered for three years then kept them penned, wasn't fair either they hated it. Sold the flock (gave away actually, hopefully to good home). Agree their call is a single-note for boys always, double-note for girls except when they choose to do single note if agitated.
If you keep some out and some penned, the free ones will not go too far away. For toys, they love pieces of chain (all sizes) they can peck at and jiggle around: this was common to all my Guineas from different sources. Include tow safety chain on trailers, dog chain holding pot-plants secure, low chain links on a gate - all spent time picking and playing with them. Funny birds, ton of personality, yes noisy too but never without a reason, even to say there's a bike going past the house (or a dog or fox or eagle or snake around that shouldn't be).
I've kept one male that was always a loner and very aggressive to all others. He doesn't seem to care about being the only one and tolerates the chooks for company.