I went and compared the specifications of the Broadwell vs Skylake cpus, here are my observations:
1. Skylake will not be available...
1. That's it.
2. Well, we haven't seen any benchmarks yet but Intel advised edge-users and gamers not to go Broadwell and wait for Skylake instead because the performance would be one of the greater steps in the decade, so I wouldn't say "just a bit" (not like from Ivy to Haswell or Haswell to Broadwell, which can't be noticed).
3. That's it. But also DDR4 (better for integrated GPU's as it will be faster memory, especially for iGPU's without eRAM). Also Thunderbolt 3.0, up to 50% more Execution Units compared to Broadwell (which has up to 20% more EU compared to Haswell...), and more stuff to see.
4. Yes, Cannonlake, but if they had problems with 14nm just imagine what will come with 10nm... Not to say that it will be like Broadwell is to Haswell: almost the same thing but a bit better energy efficient.
5. Well Apple makes its own calendars. MBA has been up to 499 days without any refresh in 2009, so Apple doesn't care about waiting a bit more months, specially if they do a rMBA with wireless charging thanks to Skylake. A rMBA with Broadwell would be a surprise but less impressive. I bet Apple will refresh MBA's soon but mantaining the actual 11" and 13" with Broadwells and HD6000's.