New preamp or up grade my cartridge and or phono amp?

I think your cartridge and TT are the best part of your system by far.

My Rega P3 with a tube preamp sounds better than anything I tried - and I tried a lot of inexpensive approaches.

And I 100% agree with you about the living room/sharing the wealth vs small room. I couldn't do a small dedicated room for many reasons. 

As with upgrading any audio component, which preamp would be driven primarily by what improvements you’re looking for and what sound characteristics are most important to you.  Bigger 3D soundstage, better tonality, etc. would be the kinds of things you should identify that you’re looking for and then go from there.  Rogue is actually interesting because it’s a neutral sounding tube pre yet still likely sounds quite a bit different from your Emotiva, and I believe Rogue is one of the few tube pre manufacturers that disables the tubes when using the HT bypass, which is really nice when you’re just watching movies or TV.  Anyway, if you can clarify more what you’re looking for you’ll get several good recommendations here. 

OP, “…Though I have a friend who went that route and his listening room wound up isolating him from the rest of the household.”

That sounds like a fantastic advantage! That is worth it by itself. 😊 oh, sorry, most audiophiles are recluses… typically the household doesn’t join in, but tell you to turn that off or put on the news. My partner is happy she can send me to my audio room and not subject her to it. She loves music, and comes down to listen for about ten minutes every decade. But there are exceptions.

If this is a step towards a long term hi-end system then I would get the highest quality tube preamp I could afford. This pieces is the heart of the system. From there you can work on source issues. The cartridge is certainly a key piece if your focus is vinyl. I would not spend money adding a better arm to the Rega table. You did not mention speakers. You must be happy with them. They are the most critical part of the chain. 

These days, what we call a preamplifier is a linestage with a bunch of selectable inputs and optionally a balance, phase, or mono control. The linestage usually adds only a little gain to its input signal, which emanates from a phono stage, CDP, or other high level source. In fact, the linestage needs an attenuator to throw away excessive gain from input sources. If the linestage is passive it adds no gain at all. I think it’s no trick to make a very low distortion, wide bandwidth linestage, and linestages need not be hyper-expensive. In fact, the most important part of a linestage is a high quality attenuator.