I think you might want to re-examine that budget after reviewing the constraints you have listed for the project
but then that only will account for which level of quality you wind up with. Id put more $$$ into the speakers than into the receiver
. As that would be the easiest to swap out later on to improve or update the system.
Using a ghost center isn't going to be an option on the newer Onkyo units. Sony used to do it, and might still... check into that aspect on any unit you investigate.
Also be advised that '2nd' zone? It may be restricted to ONLY analog connected sources or the tuner... the 805/875 Onkyo IS LIKE THAT... AND MANY ARE. Top tier units might allow for digital sources via the second zone though... and some dedicated processors
. Look for that item as well. A call to the whoever supports team will clarify things as their press is quite veiled regarding such alternative zone uses. A second amp too might be required so do look into that area closely.
In my Onkyo based HT rig, I bought a dedicated center ch speaker which matches my mains.... reportedly. It doesn't. It does however provide the fill and center ch info being generated in multi ch audio with a very good blend and is a positive addition... but it's not voiced exactly to the mains, as complimentary as it is in fact.
My Sony, where I run the ghost due to space and placement considerations in my 14 by 12 ft. bedroom, is as enjoyable... to me. Go Figure.
The obvious diff between the two is what I term 'distinctive dynamics'. A defined point source projecting info and filling up a more cohesive symmetrical array is noticeably a nicer thing. Given side by side, right there and then comparisons, I think most would agree. Otherwise, either way can be quite acceptable ordinarily.
Not going with a center right off will save $$$ too. Once into it, one can be added later on if needed.
As I said, each method is quite enjoyable. Having better mains for this non center ch exp is a good thing too.... but I don't feel it is a necessity.
Getting a rec with the HDMI 1.3 option is going to be a great cost cutting measure too and allow for moves into Blue Ray and less cabling costs.
Bare in mind as well... 2 ch audio is my passion, I'm more geared to practicality, price to performance coefficients, and am pretty OK with not having the exact best possible situations more often than not in my non main listening systems. That said, I really dig the multi ch audio scene with well done DVDs or live events. The latter often suffers better reproduction.
Don't get me wrong here... I am quite picky... very much so... but I also realize which world I live in, its inherent financial logistics, priorities, and constraints.
Consequently, compromise is not a word I am unfamiliar with and I'm now capable of living with it with greater ease.
Lastly, given all the dedicated info swirling about from each speaker, be it 4, 5 or 7, that '0.1' ch is oh so important... especially with either on wall or limited range stand mounted two ways... which I strongly suggest over any on wall speakers. Phase Technologies, does a great job in HT presenting an outstanding value, yet seldom get the press they deserve and have great customer support if it is ever needed... though I doubt it will. They have a new line of on/in wall HT speakers that profess a general sweet spot ranging across the span of the seating area... they will be cost prohibitive.... coming in around 15K + for the setup. It does say though, that they have the insights and expertise for high end HT applications.
Were I to be on a severe budget Id look into using bipolar speakers like from Mirage, or Eros, or Phase Tech. Getting them used might be an issue though. Other threads here illuminate their use in HT better than I can... and regular theaters do use them a lot.
Look into Vampire or Canare spool wire for speaker cabling. Theyre both a good way to go. Ive used both with great success.
Good luck, really.