Your center and L/R choice are fine with either $10/box returns at Crutchfield or free returns at Best Buy but I'm not sure if they are carrying those any more. If they are they will price match Crutchfield.
As to the in walls I'd get, for the same price, the superior "matching" Pro RP in walls.
Here are the best choices for subs IMHO; pay close attention to the cabinet size so you don't get shocked at how big some of the powerful ported subs can be.
PORTED SUBWOOFERS $600 AND BELOW, DELIVERED
*IF LOOKING AT LARGER/MORE EXPENSIVE SUBWOOFERS ADD PSA TO THE LIST OF BRANDS
*IF YOU ARE NOT AN ACTION MOVIE FAN A SUBWOOFER WITH 22-30HZ EXTENSION WOULD BE FINE
*FOR MUSIC A 30HZ SUB IS A FINE CHOICE
Specs are from the manufacturer unless noted otherwise.
150watts =11w18h13d= 18 lbs 8" [28hz] $199 EMOTIVA BASX S8
200watts =14w16h16d= 34 lbs 10" [27hz] $299 EMOTIVA BASX S10
350watts =15w16h17d= 40 lbs 10" [30hz] $399 RSL SPEEDWOOFER 10S, (extension from Sound & Vision review)
200watts =14w15h15d= 32 lbs 10" [25hz] $450 ELAC DEBUT 2.0 SUB3010, (extension from Sound & Vision review)
NOTE: THIS SUB HAS PHONE APP EQ FOR THE SUB
250watts =15w19h17d= 42 lbs 10" [25hz] $455 HSU VTF 1 MK3 (extension from Audioholics review)
300watts =15w19h20d= 46 lbs 10" [18hz] $499 SVS PB1000, (extension from Sound & Vision Review)
500watts =15w19h20d= 72 lbs 10" [20hz] $500 MONOPRICE MONOLITH THX 10"
300watts =16w22h21d= 69 lbs* 12" [19hz] $549 RHYTHMIK LV12R
350watts =15w21h22d= 62 lbs 12" [18hz] $607 HSU VTF2 MK5, (extension from Audioholics review)
* = shipping weight