Recommend some relatively recent releases (2013 and onward...) to listen to that will help fill the void of their absence.

I know Renée Neufville and Jean Norris-Baylor of Zhane are still around, singing on various projects. One of my more recent favs from Renée is her contribution to SERAVINCE's "Here To See" album from 2015.
"Perfect Stranger" is that shit.
https://www.youtube.com/watch?v=9u1GVI14quY

Renee dropped a solo song during the same year that jammin, too. Hopefully, she's still working on an album, if she ever was. She's active on Instagram.
http://www.soulbounce.com/2015/10/renee-neufvilles-solo-debut-has-us-watching-and-waiting-for-more/

I saw a recent photo of the Jazzies on Instagram. They look great. They have to be 45+ now...

As an aside, please don't rattle off a list of the following current indie R&B duos because I already know about 'em (and I adore many of them, too). Of course, some are not quite filling the Zhané/ JazzyFatNastees void for me.
St. Beauty (Janelle Monae's protégés)
VANJESS
Chloe x Halle (Beyoncé protégés)
OSHUN
Ibeyi

Oh, and since I have y'alls attention: The JazzyFatNastees were a quartet signed to Tommy Boy in the early nineties before their debut, Once and The Future, came out. Did they ever record material that just never came out? I sure would love to hear what those songs sounded like...

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"Music is not to be possessed; it's to be shared.” - James Mtume

"Just stay loose, keep it raw, and bang ya drums out sometimes." - Madlib