It has been about a week and you seem to have gotten no replies, at least here. Might I suggest that forums don't handle multiple issues under one subject very well. Try taking one of your issues and posting it with its own subject line.

I'm not at all sure it's a matter of having posted four different plants in one post. I think it may be more related to the fact that the plants (at least three of them) aren't all that common for most of us. Google will provide some help if searches such as

"Philadelphus mexicanus" cuttings

or

"Philadelphus mexicanus" propagation

are employeed. I haven't personally tried propagating any of the the four, so am unable to provide any personal insight.

Specifics on what you have tried (that didn't work) might also possibly bring out some helpful information. If you have lots of propagation experience and are still having problems, that would likely be very different than someone who was trying these four plants for their first attempts at propagation. With the information provided, we can't really tell where you are in this continuum, or, what you have tried.