Can this sub arrangement work, please sub pro's?

It is hard to know what you are asking. Yes, physically,
you can put each Pulsar on top of each sub but you would be
advised to put spikes under the subs or otherwise secure
them to the floor. Also, you need to determine how much
those subs vibrate since that energy will be transmitted to
the Pulsars.

As for hook-up, you have 3 options. One is to buy an
external crossover. The second is to replace your preamp
with one that has sub outs and crossovers. The third is to
get subs with built in HP and LP filters because the PSBs
have only LP filters.

However, my recommendation is to buy a comparable floor-
stander which would make better use of the same real estate.
(The stand for the Pulsars makes no acoustical
contribution.) Guessing your budget from your prospective
purchases, there are many excellent speakers in the $10K
range but I would suggest a pair of Aerial 7Ts. You would
get great sound and avoid all the complications. The are
tall but graceful and beautifully finished.

Kr4, why cant the second set of outputs in the EAR 868 go to the sub? Doesnt the sub have crossovers?

Sure but then you will have no HP filter on the main speakers. That means (1) increased stress and lowered power handling on them and (2) difficulty in balancing/aligning the subs with them.

You might consider these:

http://www.vienna-acoustics.com/products/Factsheets/12_Schoenberg_V02_WEB150.pdf

I use them in my HT room (with subs). They look great and sound more than very good (tho perhaps somewhat less than truly great) in 2 channel use IMHO. As a WAF compromise, these are worth checking out.

As to x-over arrangements for your subs - I'd always choose to cross in the digital domain, particularly if you don't use vinyl (or other analog) source material. A good pre-pro or something like the HK 990 integrated amp would allow this and would provide digital room correction, as well. I've never managed to get seamless sub/main integration without going this route. Of course, YMMV.

Good luck.

Marty