Preamp recommendation

As far as the amps, it's difficult.

The Monoprice Monolith is currently going to be the most transparent, cleanest and highest resolution of the three.  It has excellent and very full midrange tones.  However, it could be a little hard edged in the highs (especially with your Focal metal domes).

The Parasound HCA is going to be very smooth and very refined.  Very natural sounding, but not as transparent.  Rolled off highs and it's not going to be as exciting as the Monoprice.

The Krell KAV-500 might be better than both of these.  Much more refined, transparent and "truer" sounding than monoprice.  More resolution and exciting than Parasound.  It is a 20 year old amp, though, if this concerns you.  I see one on audiogon for $1400.  If you can get one in good condition for $1k, it might be really excellent.  I have no idea when these will start failing due to dried out capacitors and other parts that may fail over time.

https://www.schiit.com/guides/choosing-amps-preamps

Home Theater Integration, $0. Okay, all you "home theater bypass" guys. All of our preamps offer true home theater bypass. Just plug in your processor's front channels to any input, select Passive mode, and turn the volume all the way up. Presto! 1:1 home theater bypass, with only a relay in the signal path.

Thanks everyone for your input. 

Looking at Parasound A51 and A52+
I am correct to assume these would sound similar ? 
What are pros and cons of each? Is the price difference justified?  

Wow, did your budget go up? lol.

The sound between the A51 and A52+ is going to be very similar (if not the same).  The main difference is power / power supply.  Your Focal Dome speakers are not going to be too terribly hard to drive, so the difference between 180 watts per channel and 250 watts per channel is not going to make any significant amount of difference (in my opinion). 

The higher power of the A51 would be beneficial if you really large woofers and low impedance speakers.  The A51 might be just a little bit more smooth and full, but it is a significant amount more.

I find that budget always goes up no matter where you start, at least this is true for me. I think I'm leaning to Parasound P7 pre, and Krell KAV500 vs. A52+. 

Before making a final decision, I'm also looking at Anthem MRX520. Do you think the sound from Parasound/Krell would be better than Anthem via Focal dome speakers? Anthem reportedly has good room correction (ARC). Not sure how much of an effect that will have on sound. 

BY THE WAY: My older Krell KAV500 failed on me a year after I got it, needed to be recapped and again, one year later making strange popping noise through speakers while its on. I love the sound of Krell via Vienna acoustics speakers.