An electronic device may include first and second laterally spaced apart interconnect substrates defining a slotted opening, and a first IC in the slotted opening and electrically coupled to one or more of the first and second interconnect substrates. The electronic device may include a first other IC over the first IC and electrically coupled to one or more of the first and second interconnect substrates, and encapsulation material over the first and second interconnect substrates, the first IC, and the first other IC.