The pleco OCR is certainly not adapted to manhua (top-down and right-to-left orientation). How likely is it to add these features to resemble apps like "OCR Manga Reader" and "Kaku" for android, Capture2text for Windows?
It's certainly doable, just not something we've had a lot of requests for. (I think manga tends to have specialized enough vocabulary etc that it's something people often prefer a dedicated app for)
I'm also a Manhua reader and this would be a great help! Most Mangas translated to Chinese have their texts written vertically and it's really frustrating not being able to use these materials.