Have a look at the contributed theme Bootstrap Business, which is a sub-theme of the Bootstrap theme. It should fit quite a few of your requirements.
Some months ago I did some type of comparison of various bootstrap subthemes, and this subtheme turned out to be the best alternative available.
If it doesn't entirely fit your requirements, I suggest you ...
you could check out pinegrow
I use and own this software like me your wife will be able to learn about css and html because you can see the the code affects the elements
it meets your requirements
namely WYSIWGY ,
easy to use,
runs on Mac
they have a trial
being actively developed
and usually have a few discounts every year ...
Perform your REST request first, and parse your JSON with JQuery to populate your <select> field.
Finally use any library like chosen to enhanced your field with autocomplete.
Warning: Initialize the plugin ( $(".chosen-select").chosen()) only after having populated it.
This will give exactly the behaviour you want.
Formvalidation.io is quite good. And if the project gets commercial it won't be too expensive to use it. But anyway, I would like to provide you an good openSource alternative.
You can try to use jqBootstrapValidation too. It's free of charge and can be downloaded on GitHub. It's published under MIT, you need to be sure that this license matches your ...
I found this: https://github.com/koss-lebedev/bootstrap-duration-picker
it is easy to use, I like it.
This plug-in add bootstrap on another jquery-duration-picker. To use this plug-in you have to include the .js and .css that they are in the src folder.
So it looks like:
Unfortunately, the months are not implemented...