Just about any speaker is compatible with that receiver, except for some esoteric low Ohm models and the occasional Bose or HTiB models that have proprietary connectors. The speakers you chose have standard binding posts and are normal range in Ohms, so have no worries. As far as 5.1 vs. 7.1 is concerned, that Onkyo, like most modern A/V receivers, is configurable to 5.1, 6.1 or 7.1 speakers.
For a sub, that SVS package comes with a PB10-NSD sub, with the option to upgrade to the PB12-NSD for $130. Depending on your room size, the upgrade may be worth it. Both subs have quite the bang-for-the-buck, but the PB12 will reach a little lower and sound a little louder in larger rooms. Either way, you'll have a great system that is better than 98% of the stuff you see in stores.