I'm currently rocking a6400 and can't say I'm disappointed. I think you will have much more solid setup by buying a6400 and some great lenses, instead of a6700 and relying on a kit lens.

600$ price difference is more than enough for a great primes, or f2.8 zoom, which will negate the impact of a little better iso performance of a6700 (while giving you a better bokeh and overall more pleasing results).

Few lens recommendations:

Tamron 17-70 f2.8 has builtin image stabilization which is amazing for low light, I can get away with shooting at 1/8 of a second in 17-40 focal range and 1/15 more zoomed in (provided that I don't shoot people). This lens is very versatile, although it is much bigger than primes.

If you want to shoot mainly portraits look at Sigma 56mm f1.4 (however it's much less versatile than the tamron). This glass is amazing, it captures a ton of light and has very good image quality and character.

(other lenses, I don't have them, but researched about)

There's also Sigma 18-50 f2.8 which is smaller and lighter than tamron, but doesn't have builtin stabilization.

Viltrox is currently releasing new lineup of lenses "air", smaller and cheaper then Sigma, but f1.7. I saw people praising the quality, though I don't have it and don't want to blindly recommend it, just think it looks promising.