I currently have a 2014 IS250 Fsport with 65k.
My wife had previously a CT200H, again previously - as in several years ago.

I see a 2016 F sport CT200H for sale, but has 69K.
I am consider trading it in for the HB, and better mpg.
However, being a bit on the higher end of mileage for a 2016....
How is the battery / cell on these hybrid? est lifespan on them?

Should consider a Prius instead?
I would not trade in unless the dealer pays my car off.

2016 CT200 F going for $18,988 before tax

Mine is 2014 IS250 F sport with BSM - Debt at $18k.

Yay or nay or go for a newer car like a 2018+ Prius HB or Civic HB?

Point is to get more room, mpg and reduce my mo. payment

 

I got my 2015 (which is the identical car to the 2016 except the 2016 gets a front chrome strip on the lower bumper) for that EXACT price but with 40k miles. Consider a 15.

The CT is great and I'm happy with mine. Once you go Lexus you can't go back to Toyota. Prius is a great car but it has the stigma of driving a Prius attached. With the CT, you get a Prius without the name =) I get about 43-44 mpg avg. On highway trips, easy 50 mpg.

You won't be getting more room with the CT vs the IS except cargo room. The CT is spacious when you fold the seats down.

Don't worry about the battery/powertrain. It's absolutely lifetime. The battery will last longer than you and is super cheap to replace even if you ever need to. shops do full replacements for 1k. 2k tops. They're commonly rebuilt and super cheap to service nowadays. But as I said they'll last a life time. Just have to clean the battery fan every 100k.

Here's my IS and CT