PPS, I would say the standard v2, at only 32GB onboard for all the OS updates, patches, DLCs and saves etc is a bit on the slim side.
If you're intending to use it as a main machine for them with multiple games, I'd definately invest in a decent performing microSD card for the system. It'd be fine for just AC, but I suspect they may play more than that!
The Switch is fine with most decent performance cards, albeit if they're on the lower side of performance it can cause stalls and hitches, so worth getting one rated U1/3 and A1, as that should guarantee it'll be up to spec for sustained transfers, installs and the like.
I'd still recommend the standard over the lite even for your 6 year old though; it has better battery life, and also the lite cannot be docked, and some games literally NEED extra joycons. The lite is more useful as a second system.
I would perhaps say go standard for your daughter, OLED for the wife as the OLED is a bit more premium and the wife may appreciate that, plus less likely to need to add a memory card due to the doubled storage
