Small room amp and speakers recommendation

KEF LS50W. Not sure if a sub is needed in such a small space.

Audience 1+1 V3 need space behind them but they weigh about 5lbs and sound huge. 

I owned the 1+1 and the KEF LS50, not LS50W. However, I needed acoustic panels in my room to make the LS50's sing. I doubt you would need acoustic treatment with the LS50W, since it has built-in DSP.

With the LS50 and 1+1 I used the Peachtree Nova 150. That would keep you under $5K for a complete system.

I also used the Benchmark DAC3 HGC and the Benchmark AHB2 with each of those speakers. I liked that combo much more than the Nova 150 however, a lot of people here may say that combo was not MUSICAL. I loved it. That combo was more than $5K.

I have a small room and think the Aerial 5  is a great speaker, and since its been around so long, you can get them used for a great price.

NHT Classic 3's with a Threshold SA/3.  All available now.

While this may hold no appeal for you, one way to really open up the budget for better electronics would be to build the Parts Express Solstice speaker kit.  These are just over 1K and will compete with speakers that would consume your entire budget.  Can't imagine you would not be thrilled with their performance.

This would be a nice system for under five grand!
SPEAKERS
https://store.acousticsounds.com/d/67911/Harbeth_Speakers-P3ESR_Speakers-Speakers
AMP

https://store.acousticsounds.com/d/88980/Rogue_Audio-
Sphinx_V2_Hybrid_Integrated_Amplifier_with_Remo...

STANDS
https://www.audioadvisor.com/prodinfo.asp?number=PGDS400