Sonus faber choices - help me decide

Before buying the Anthem STR integrated amp, you should know that Anthem also makes the STR preamp, which has a more sophisticated ability to independently integrate not only one, but two subs with ARC correction and also use them when you are doing home theater. So, you may not even need the Y splitting for your subs.

You already have a power amp for the front L/R channels, so I'm not sure why you would need the STR Integrated amp at all. 

I'm not sure the STR Integrated will drive your front L/R speakers any better than your 200 wpc Rotel.

As to the speakers, I'm a sucker for big floor standers, so I would be all over the Amati's if I could swing it!

Well I would take the better speaker every time. 
 

yes you can connect most subs to both a two channel preamp and receiver at the same time. It is important to have the inputs sum. If they don’t it will not work so read your manual or give them a call. I do this with my JLs and it works well.
 

I would also encourage a higher crossover. Your subs are better than the speakers below 80hz for sure. Try 60, I bet you get more impact and lose nothing. 

Final update. I just talked to my local dealer. He has been selling Sf for years, and cautioned me against buying something as old as the Futuras. He actually gave me a deal. He is going to sell me the Nova V speakers at the same price I was going to pay for the Futuras. He says he has the newer Amati speakers at home, and the Novas are so close to them that he would have bought Novas if they were available when he bought the Amatis.

The only downside is that I have to wait for the Nova V's to come in. Fingers crossed it won't be months.

Good to hear and good choice. I love the nova III and the V will be great.

Please report your impressions on the V's after you get them (and after the burn in).

I don't know about the newer Amati speakers, but I can tell you there is a huge difference in scale between the Amati Futura and the Nova II. Nova V might be a different story, I don't know. But this came from the dealer selling the Nova's so should be taken with a grain of salt I think. Speaking of which, why more exactly did he caution you against buying "something as old as the Futuras"?