No idea, we have to finish the Mac version first and then release it and look at how it does sales-wise for a while to see whether it's actually worth pursuing a PC version.
Are iOS and macOS Pleco versions gonna be released together?
That's great!Final release probably, but the beta will be iOS first. It may even be missing an iPad version in the initial beta, because frankly we'll get more than enough feedback from the first beta even without it and it'll save a little time if we don't have to make the iPad version presentable for that release. (there's actually a lot more iPad-specific code now than in 3.0, due to a combination of a navigation / UI revamp and some iPad-specific functionality like keyboard and mouse input)
If you have another Apple device, Apple’s Universal Clipboard lets you cut-and-paste from your Mac directly onto the other Apple device (and vice-versa). I frequently cut-and-paste from Skype on Mac directly into my iPad’s Pleco.