Apple doesn't buy manufacturing companies, however if you can make something they want, they have definitely been known to pay for a dedicated manufacturing line up front.

Risky. Apple loves to vertically integrate and they could certainly give a cash infusion, but right now they can bounce between TSMC, Intel and Samsung and probably get sweetheart deals at each because of their scale / the positive press from serving Apple as a customer.

Buyer could not fire existing customers, as Broadcom did with VMware.