The Yashicas can use the Zeiss glass, but will the cost of those lenses stop you from buying the lenses you want?

Almost any system that you can afford will be just fine. You didn't list anything in the way of "features" that you want or what your budget is, so I'll make some assumptions based on what you said you've used: You're willing to use a manual focus camera as long as it has a meter, and you're probably interested in "general photography" so you're not yet looking for anything terribly exotic. You want to be able to afford a camera and a few lenses without spending a lot of money.

The Yashica is fine as long as you can get the lenses you want. If you'll be buying the Yashica lenses rather than the Zeiss lenses because of cost constraints, then I'd suggest you look at something like an old Pentax K1000 or even a Pentax Spotmatic (screw-mount) instead. You'll be able to afford a lot of good lenses for one of those cameras, and the cameras are built like tanks. The old Pentax lenses were some of the best around, especially if you stick with Super-Multi Coated ("SMC") lenses.

As an example of the price difference: KEH sells the Zeiss 50mm f/1.7 for the Yashica in Bargain condition for US$62. (This is by far the cheapest Zeiss lens they list; most of the Zeiss lenses run anywhere from US$200 - US$600.) They sell the Pentax screwmount SMC 50mm f/1.4 in Bargain condition for $US35, and most of the lenses for the Pentax screwmount sell for under US$100.

For the price of the cheapest (Bargain condition) 180mm Zeiss lens that KEH lists (US$349), you could buy Pentax screwmount lenses in the following lengths: 200mm, 135mm, 105mm, 50mm, 35mm, and 28mm...plus a Spotmatic camera body. And you'd still have a couple of dollars left.

I love Zeiss lenses, but unless you're sure you're going to be able to afford them, I think you'll be happier with a camera that allows you to purchase good lenses at a fair price and that will last you until you decide to upgrade (either to a higher-end 35mm camera system or to larger film). Besides, the Pentax Spotmatic and K1000 cameras seem to run forever. You could probably buy a well used system today and use it for the rest of your life.

Be well.
Dave