At a guess, the Blues will stay with the Hornet for quite a while. However the next aircraft will probably also be a Hornet. They fly the legacy aircraft now, but they will likely transition into the Super Hornet in the next few years. The C/D legacy aircraft have a few more years of use, and the Blues recently went to them from the A/B. The E/F will probably be in the fleet until well into the 2030's. After that, who knows, but if I were to bet I would say the F-35.
The Blues have always used operational aircraft, and there are really no current planned additions to Naval aviation beyond the F-35. I am sure there will be something else, but nothing on the looming horizon right now. Of course, the F/A-XX (Next Generation Air Dominance) fighter might be coming in the mid-late 2020's, but who knows if that one will ever really be funded or in what numbers.
So, F/A-18 C/D for right now, into the E/F in a few years, and then into the F-35 for a long run.
Similarly, the Thunderbirds will probably continue to use the F-16 for a few more years. Personally I doubt they ever go to the F-22, there are just too few of them and they will want to keep them operational, but I rather think they will go to an aircraft the Air Force has in numbers, probably the F-35.
1969 to 1973 both the Blues and the Thunderbirds flew the Phantom II, the Blues with the F4J and the Thunderbirds with the F4E. We may see something like that again when both fly the F-35, the Blues with the F-35C and the Thunderbirds with the F-35A.
T!