I think I can answer at least some of your questions. You may want to consider doing some research to see how APNs are being utilized at the hospitals near you, because there are regional differences. I'm in TX and everyone around here seems to have AC NPs, not CNSs. I know the popularity of CNSs has diminished in preference to NPs. This is partly due to the fact that NPs can bill directly for reimbursement, whereas CNSs are an expense to the hospital just like staff nurses. Scope of practice may differ among states, but CNSs generally focus more on education and care coordination. Whereas NPs function very similarly as residents. Where I work the ACPNPs can intubate, put in CVLs, art lines, chest tubes, run codes, and generally field all of the questions/concerns regarding patients from the nursing staff. Generally CNSs in TX don't have prescriptive authority, whereas NPs can prescribe anything within their scope of practice other than Schedule II drugs. So depending on what you want to do and what jobs there are in your area should lean you toward either CNS or ACNP. I'm not aware of any dual degree programs.
As for what school you go to, that has been asked on this forum a lot and the answer is always that it doesn't really matter where you go to school in terms of getting jobs afterward. I would recommend comparing the curriculum of the different schools
you are interested in and pick the one that seems the best. There is a lot of variation between schools. I chose to go to an online school (UAB), because their curriculum was much better than the school that is here locally. I had also heard very good things about their program, and so far have not been disappointed. I wouldn't discount a school just because it offers an online program.
Be thankful that you did well in your prior schooling, so you should be able to get in. Every school I have talked to has said they've seen a dramatic increase in the number of applications recently. I work with several nurses who have applied and not gotten into grad school and there are lots of people on these boards who haven't been able to get in. I haven't heard of any programs being "easy" to get into lately. At least not the NP programs. Good luck with your search!