Sorry for the confusion - we do use the same ABC Comprehensive Dictionary as Wenlin, but in most other respects we're a completely different product.
You can get single-character frequency numbers in PlecoDict using the Unihan add-on database; go to
http://www.pleco.com/dictaddons.html to download and install it. Once it's installed, you can look up a character in the Unihan dictionary to get its frequency (ranked 1-5) and various other useful information about it. We don't currently offer frequency information for multiple-character words, but it's certainly something we could look into adding, as there are numerous databases of that information available for free online. I think you're actually the first person who's asked for this feature - if you don't mind my asking, how exactly do you use the frequency information in your studies? How do you think adding it would benefit Pleco users?
Wenlin's character history sections are actually something they developed on their own, I believe - they do excerpt Karlgren and several other works, but I'm pretty sure Wenlin compiled the entries themselves. I suppose we might be able to license that data from Wenlin, but I think a better choice for us would be something shorter, along the lines of the character info from Zhongwen Zipu (
http://www.zhongwen.com/) - on a PDA screen the Wenlin entries might be longer than people would want to read, and if all you're looking for is something to help remember a character, you really don't need more than a very brief description of the character's components and how they fit together.