Intel's 80C186 re-do of the 186 seems to have been sampled in September 1987:
https://www.cbronline.com/news/intel_sa ... 0186_chip/

Wikipedia says "The 68HC000, the first CMOS version of the 68000, was designed by Hitachi and jointly introduced in 1985"

There's RCA's COSMAC, the 1802, from 1974. Had an 8 bit accumulator but "also included another set of sixteen 16-bit wide general-purpose registers." "The 16-bit registers can be incremented and decremented with single instructions" although in most other cases, it seems, the program needs to proceed byte by byte.
https://en.wikipedia.org/wiki/RCA_1802

There's a problem in that '16 bit processor' is subject to any number of caveats or interpretations. I've no doubt this thread will explore some of the space... remember everyone, there is no right answer.

So that would mean the 65C816 did predate CMOS versions of Intel and Motorola product, since the '816 was available in 1984, at least as samples.

The 8OC86 is packaged in industry-standard, 40-pin, 0.6-inch-center ceramic and plastic DIPs. A 44-pin, JEDEC-compatible leadless chip carrier package will be available in the fourth quarter of 1983.
Future extensions to the family will include an 8-MHz version of the 80C86, a serial communications interface, octal bus transceivers, a bus arbiter, a DMA controller, and an 8/16-bit microprocessor. Most of these devices will be available for sampling in the fourth quarter of 1983. The last two will be available in the first quarter of 1984.

The Zilog Z8000 was 16-bit and released in 1979 but was it CMOS?