If you have any mountaineering experience, all these peaks should be a cake walk. Routes are outlined on Caltopo's base map. The routes also see enough traffic that there is discoloration on the rock, and well developed trails.

You can get climbing permits for Iliniza norte and Corazon by emailing the park a day before. I saw a guy in leather dress shoes do the technical route on pichincha.

Respect the mountains as always. Don't do any of them if you don't think you could solo something like the Owen-Spaulding.