I would also submit that the Aegirs would heat up and possibly shut down occasionally as they are not recommended for 4 ohm loads when running as monoblocks.
I've been on an audio journey the last 3 or so years. I owned the C326BEE, the C356BEE and the C375BEE.(the big let down of the NAD line is the pre amp sections are weak) Also some Adcom amps and the Parasound P5, after selling the A21 and P7 to start over. I went through too many speakers from Tannoy, Paradigm and Totem Acoustic to mention.
I will give a vote of confidence to Schiit Audio. Their stuff isn't just good for the money. Their Freya+ and Multibit dacs are shockingly excellent sounding period. I would get you to change up your plan and replace the Nad.
Get a Schiit Freya+ and either the Vidar or Aegir, depending on the speakers you decide on. You'll be way under the 3000 budget and your ears will thank you. You'd also need the Mani phono pre. Or, if you're going to get efficient speakers above 93db or so, the Ragnarok integrated with phono built in would be an option.
The LRS speakers need to be placed at least 3 feet away from any walls. The LS50 are somewhat bright sounding, depending on speaker cables. I like your idea of cycling in speakers, it's what I ended up doing. Any of the speakers on your list could work depending on the provisos I mentioned.