Where to go next with cat introductions?

I brought home a new kitty, Nova!. She's 8 months old... The same age as my current kitty, Meeko. And I'm kind of lost as to how to continue the introductions.

She's very friendly toward humans but she's very wary about Meeko.

Meeko on the other hand.. He wants to play with everyone and everything.. Humans, cats, dogs, ferrets. Not shy. So he's been perfectly fine with Nova. No hissing on his end.

Well, I've been working with them and they're able to be in the same room for the most part without Nova growling and hissing. But what happens is she'll play and groom herself just feet
away from Meeko, but will growl and hiss and swat if he gets too close. Meeko has been badly wanting to play with her or at least sniff her. But I think he's getting frustrated. Today he would jump on the coffee table where she was hiding under and try to swat at her. Still no hissing or growling on his end.

I keep them separated while I'm at work and we take "breaks" while getting together in the evening.. I live in a one bedroom apartment so Nova had the bathroom all to herself and Meeko gets to roam the rest of the apartment. I have a washer/dryer room where his stuff is at but I can't lock him in there because he howls and cries until get out. I have neighbors below me who probably don't appreciate that. I feel bad keeping Nova in the bathroom, she doesn't cry so it's the best option to avoid a noise complaint.

So I'm hoping to get them at least tolerant of each other so our living situation is more happy My strategy has been to keep them playing while near each other and to give the occasional treat. Should I keep going with this or are there any other tips anyone has to help?

Honestly, your strategy of using 'play sessions' to get both cats comfortable around each other is very good.

And ending every good 'play session' with treats, or food that they like, is really good, because it enforces good interactions, and ends on a positive note.

The only thing that I would suggest is trying 'harness training' both cats, but especially Meeko.

This way, you can keep some physical control over Meeko, in the apartment, for the times that you are all together, and teach him to not always go after Nova.

Nova, should be becoming more used to Meeko, but if she was from a litter, where she did not have a lot of interaction, or taken too young from her littermates, then she may not have learned how to play without growling, or hissing. She may also just be more timid, and needs extra time to get used to her new place, and Meeko's constant attention.

It is difficult when one cat has more of a play mode, and the other just wants to chill and relax.

Can you also offer Nova vertical places to escape to...such as high cat shelves, cat trees, bookcases,...or tables, boxes.

And also give Meeko, areas where he can lay about, too.

Even using some interactive play toys, like treat puzzles, or ping pong balls, track toys, to keep Meeko interested and entertained would help.

(Both cats are absolutely gorgeous, btw...and from the photo, the ears on Meeko, don't look flattened or frightened, so your idea of tiring both cats out with play, should really work.)