For S1 obviously...   Don't need the preamps and I guess continue to use my current interface in addition?
NOT recording large bands.  Home studio, typically one track at a time.  Looking for best DAW control.
Would like to sort this decision out too and purchase all at once with S1

If you're not going to do anything live, or record a band,
I'd go Faderport.  The single would do all you want and
it's about half the price.  

If you plan on "growing" or doing Live sound eventually
I'd go Studio Live

Have you seen this from Icon?  It uses either Mackie or HUI...
Looks kewl.  A bit pricier than the Faderport 8...

https://www.americanmusical.com/Item--i-ICN-QCONPROX

This one is $499.99 from Icon

https://www.bhphotovideo....gwFEAEYASACEgI5ffD_BwE

I have the FP16 and Presonus released an update today for its integration with S1. It is really outstanding!
You get all the advantages or motorized faders and automation as well as control of busses, VCA's, EFX, audio and midi groupings. 
They did a great job with it. The software/hardware integration with Presonus products continues to show how committed they are in these fields. It is very impressive. 
Watch some videos on it if you can. 

fp8 is great in s1 pro, but there is 16 channel version also..
 
if you have android you can also use that screen.. and it's handy to record if you aren't near the pc. muck around with faders.. it's a free download, on ipad also IRC.. there is a "demo" mode abnd you can se the functionality
 
the fp8 does support MCU / HUI but far better in s1 pro, and it just finds it.
 

My faderport 8 is on the way.

The single channel faderport works VERY well in Studio One.  I never knew what the "Mix" button was for.  It opens and closes the Console!  Sweet!

There are a few options from the Presonus hardware range.
 
The Faderport 8/16 of course and I like the direction they are taking. The other mixer in their range also can control Studio One is the CS18Ai being able to get into complete surface control over Studio One. Not many inputs though so if you are wanting to receive lots of signals then you can get add-ons which expand the CS18Ai.  
 
The live series offer lots of inputs and can send multiple channels for recording to Studio One but in terms of deeper integration, Faderport and CS18Ai are very powerful control surfaces for Studio One. 

NO!!!   Do NOT get a CS18ai thinking you can use the inputs/outputs on it unless you already own an RM16 or RM32.
PreSonus tried to use AVB for the audio transport before AVB was properly ratified (it still isn't but that's a different thread) and as a result it will ONLY send audio to the RM rack units.
 
It will work, as Jeff suggested, as a control surface for SO3 Pro, but NO AUDIO.