As far as which frequencies on her vocal it jut seems like too much low end was cut from her vocals.
And the mid range seems a little funky at times. 5-10k may need a little tweaking too, but I'd say it's more givin her some low end back in her vocals.
As far as how wide the keys should be, try out both. See what works.
As far as reverb, I liked how your track wasn't swimming in verb.
I think maybe just like a slight emt 250 style might work, but fiddle around. Not a lot, just enough to give them a sense of unity