- You have to bring image and caption together. You can do it either with grouping them or you can anchor the image to the text frame. Which makes sense for you, depends on the kind of layout and workflow.
- Now you can either anchor the group or the parent text frame into the text.
- Most probably you have to adjust the design, probably insert text frames where you want to anchor the images etc. All depends on your layout. If I create an EPUB with fluid layout I would not use a multi column document, so you might to do some additional work here too.
1. By bringing image and caption together, I assume there is a method for doing that, but I have not yet found it. If I can link them, I know how to place an anchored object in the text.
3. Since my book is printed in landscape format, my cover design is not adaptable to a portrait orientation. What are the consequences of an ebook formatted in two column landscape?
To 1: I have told you, what you have to do, follow it.
To 3: I have spoken from the the setup of YOUR INDESIGN FILE, not the EPUB. You can set up in the object style the maximum width of your column, but you are not able to decide, if your reader is reading your EPUB in lnadscape or in portrait. Forget it. The user turns his device like he prefers, he stretches the window of the reading app as he likes, you have no influence to it how he is using your EPUB. You have no influence which program he is using and which features are dismissed. If you want to force the reader to use landscape, you have to create an EPUB with fixed layout, not liquid layout. The number of columns with liquid layout does not follow the number of columns from the InDesign file, but the settings of the text frame object style in InDesign, most probably the maximal column widths settings. If you need to anchor images in InDesign, so it would be much easiear to do it in a single column file with non-facing pages which has ojhter conditions than the same printed book.
Nodeless it sounds like you do not understand grouping. To bring the image and caption together you need to select both the image and the caption then go to object--group.