For your budget those speakers in my opinion are good speakers. For the longest time I used a V2CC and 2 nano CC for my front stage with 4 nanos and a S8 in a 20x25 room with hardwood floors and vaulted ceilings. I was happy until I made HT my hobby and then there was poison in the well.
If you can get the OS3-Sat by expanding your budget then do that but if not the OS3-fs will not overpower the nanos for Movies but you may not like the mix if you plan to use multichannel stereo. Also you should get a Mirage center, if you can get that now by taking a hit in the subwoofer then do that since you can use any subwoofer really but you shouldnt mix and match Mirage fronts with other centers. If not then you may want to seek other brands that you can mix and match with.
If you choose to go with the Mirage and you like the omnipolar sound then I think you will enjoy them. Just take some time to stash some money for a sub at a later date, since you are really wanting to stay within a budget the subs you can get for a low price won't go down as low as you will want anyway. You will probably need to spend between 300-500 to find a sub that is 24hz and below anyway. Heck if anything get the S8 and call it a day, despite what some may say the S8 served me well for years. If it means a full set-up then I say go for it.