Integrated Amps

@bipod72, I use the optical output from my LG OLED TV to my Bricasti DAC and it connects to my MF M6Si integrated amp.

Whilst noting comments to my input of the NAD C399 that its not the warmest of amps (none of the Hypex are) it does also have an E-ARC HDMI, so probably simplest connection for you from the TV.

With regard to the speakers if they are similar priced in the US (they are in the UK) then might I suggest as an additional audition to the Monitor Audio 300 7G's the Acoustic Energy AE 320  and AE 509.   When the NAD C399 was bought I had some slightly old generation Monitor Audio Gold's and we tried them against some borrowed for audition Acoustic Energy's and I was impressed enough by the difference buy my step-daughter/son-in-law the Acoustic Energy's when I could have just let them have the older Monitor Audio's.   

Currently own the Musical Fidelity M6si500. Absolutely crushes most amps at the price point. Get an open box or used, for even more value.

I use the preamp outs on these to power my subs

Powerhouse 500w@8ohms weighing in at 30KGS.

From what I've read the Billie headphone amp is not very good. The amp also has hiss. I have not auditioned one though. The Musical Fidelity amps are dead quiet, sound very good and the build quality is excellent. I have an M6si and it's great for the price but as you know it does not have a headphone amp.