I'd take a look at the Cooler Master Master Liquid 240 (not the 240L). It's a great AIO liquid cooler with a 240mm radiator. You can usually get one for under $70. Keeps my 8600k in great temp ranges. Have fun.

I think its worth going for a 500GB-1TB M.2 SSD. Either the Crucial MX500 M.2 which is about $190 for 1TB or the Samsung 970 EVO, which is about twice as expensive but also performs much faster.

The cheapest 500GB M.2 I could find (<$90): https://pcpartpicker.com/product/6j448d/western-digital-blue-500gb-m2-2280-solid-state-drive-wds500g2b0b

The cheapest 1TB M.2 I could find ($174 on newegg): https://pcpartpicker.com/product/DgJtt6/western-digital-blue-1tb-m2-2280-solid-state-drive-wds100t2b0b

Also, how much do you want water cooling? If you value it highly aesthetically then that's fine but if it's just keeping the computer cool, an air cooler will work just fine and it'll save up to $100.

It should also be noted that if she really doesn't play strenuous games and isn't expecting to play on really high settings, the builds you have are very overkill. I'll comment a significantly cheaper possible build later.

Also, will she play on a 60Hz monitor or something higher?

If she isnt playing very demanding games then theres no real point getting a 1080, honestly a 1060 6gb would be fine. Although her budget is quite high so a 1070 would be more suited. That cpu cooler is really overkill for the 8600k. You could also get a cheaper 144hz monitor.