Really....
So what is the best all-around canvas that I can use for printing and image manipulation in one control?
I have no idea.
For printing all support it in one way or an other, for image manipulation aggpas is more vector oriented with a superb rasterizer that has the notion of pipelines, used to apply rasterization to what ever underline buffer you have for the image ee you might need to write a pipeline for the HDC/BMP. BGRABitmap has its own Canvas and routines to copy it to any supported widgetset's DC after painting, graphics32 is more windows minded uses a 32bit DIB under the hood and that is compatible with everything in windows.
All have a number of image filters and effects implemented so depends heavily on what you need to use or which it feels comfortable to you. And of course GDI+ can do almost everything but has no ready made effects or filters but there are some pascal headers to work with on the net.
I guess the main question is what you want out of such a library? Controls that make your life easier ee a painter that can load, zoom, pan etc images? Do you plan to work with huge image and need some kind of buffering mechanism which no one has as far as I know? At this point the best thing I can do is point you to their respective repos.
Keep in mind that BGRABitmap was create in lazarus for lazarus and is not a port of any other library also the author of the library is somewhat active on this forums it has a small group of followers and it probably is easier to find help, GDI+ on the other hand has a huge number of examples use cases and articles online so you might not need to find a person for help. In any case its up to you to choose I can't recommend any specific libraries at this point I haven't test them all and I would do you a disservice instead of helping.