Hi Jennifer,
Thank you for your questions, I will take them one a a time.
1. I would suggest making a separate cayenne infused oil. You could do this by infusing cayenne powder from the grocery store or if you are near farmers markets or a natural health food store you might be able to find dried ceyenne or chili’s, or fresher (more potent) powder that you could infuse in. I would recommend blending it up with the oil a few times over a 24 hour period then straining that. It makes a wonderful oil, but be careful, she’s gonna be spicy on any sensitive skin areas. Once the cayenne oil is made, then add this to your various other oils as needed to make salves.
2. The simple answer is either the fresh plants bruised as a plaster or an oil will work well. Keep in mind how messy fresh plasters can be (and a bit risky with cayenne-hard to keep out of eyes etc.) Oils are effective and perhaps a bit more tidy, therefore more likely to be used (out of my experience). I like plasters for their potency but have found that people are unlikely to do them more than once since it can be a bit of extra work to prepare each time and then clean up.
3. Rose, hmmm I am still unsure of this one myself. If you have a really nice drying area where you don’t loose many of the volatile oils during drying, then I would suggest drying the petals (and the buds, calyx if you wish), then do the method with a quick re-hydration with alcohol, followed by the blending the oil a few times over a course of 12-24 hours, as suggested with cayenne. This might extract more deeply. I have found rose oil to be tricky to extract otherwise.
I hope this helps, it sounds like you are going to have fun making incredible topical herbal support.
Benna