Will Unity pro plugins will work on Unity free version?

Hello,

I’m developing an SDK for Unity apps, using the free trial version of unity.
Since I want to use uWebKit to display web pages inside the Unity player, I am planning to purchase Unity Pro.
My question is - If I develop the SDK using Unity Pro, with plugins and controls that support only Unity Pro, will users with the free version be able to use my SDK?

Well, no, that’s kind of the point of Pro, namely that Pro features don’t work in the free license. If they did there’d be no reason to buy Pro.