I'm getting my wife the Moto G5, which can come with 2GB, 3GB, or 4GB of RAM. It comes with Android 7, but I think the Android 8 upgrade is available.
My wife isn't a power user: she uses Whatsapp occasionally during the day, does email occasionally on the go, reads the news online, and our toddler watches youtube on it occasionally, takes photos occasionally. She doesn't store a lot of stuff on it like movies or photos, so storage space is largely irrelevant. She doesn't need to multi-task, and she's not even bothered by the speed of her horribly slow G1 - which is about 10X slower than my phone and drives me nuts how slow it is.
2GB RAM + 32GB storage = US$164 (ships to NZ)
3GB RAM + 16GB storage = US$165 + $15 for 16GB memory card (ships to NZ)
This one is rare and probably not possible to practically get: 4GB RAM + 32GB = US$220 + $30 reshipper = US$240 (goes via reshipper, prime members only so I can't easily get it)
My own phone is a Huawei P9 with 32GB of internal storage. Of that 6GB is apps, 7GB is system data, 11GB is free (total 24GB so far), and 8GB is presumable used by a ROM. 16GB could be a bit tight unless you have an external SD card that the phone can effectively use.
Question 1) Is 32GB storage required?
Question 2) Is more than 2GB RAM required for a casual user with low expectations?
Question 3) Can Android 7 / 8 effectively use an SD card to increase useful storage? Saving apps to it and running at a decent speed, etc.
I'm leaning towards the 3GB RAM one, seems like a good compromise and might be better for Android 8.