Novel ultra-compact sub-10nm XOR, NOR and NAND CMOS logic circuits based on ambipolar characteristics of Schottky-Barrier (SB) FinFET devices and gate metal workfunction engineering are introduced. Use of SB source and drain contacts, high-k gate dielectrics and ultra-thin body bestows extreme short-channel immunity to the proposed FinFETs with ambipolar current-voltage characteristics. Thus, the main physical parameter left for practical device design and threshold control is the gate workfunction along with independent-gate drive, which is creatively used in this work to build a novel conjugate (n/p channel) CMOS pass-gate transistor that can function as a two-transistor (2T) XOR gates as opposed to 4 transistor conventional pass-gates. In a similar fashion, gate workfunction engineering can be utilized to design unique ambipolar FinFETs with two independent gates and high thresholds to function as 2T NAND and NOR gates. Functionality of the proposed minimalist logic circuits are verified with Synopsys TCAD simulations, which indicate that optimized gate work-functions lead to CMOS logic circuits as small as 5nm and supply voltage of 0.6V, with a power-delay product at 5 χ 10-18 J level.