If you look at most schools, when there is an HC change there are actually very few recruit losses (although I expect Auburn may be the exception). The current staff usually has a sort of 1-2-3 list and has communicated that to the recruits. These are the kids most likely to move on with a coaching change.
So, if you are recruiting a 4-star QB, but haven't quite reeled him in, you might tell a 3-star kid, "We'd like to have you, but we only have room for one QB this year and Rocky Steelarm is our guy. You can greyshirt if you want, but we might not have a schollie until next January." Old coach leaves, new coach comes in. He continues to pursue Rocky, but his number two is a bit hazier and might actually drop off to a number three.
Here is the only problem that I would see with Russell over the next six or seven weeks. I KNOW that he was reaching out to programs after Croom left. It was also being done from the slant of wanting the staff to call him as opposed him contacting the staff. Guys do this when they want to be able to say to their HS or their recruiter that the other coaches called him, not the reverse. Still, having said that, I presume he is yours to lose.