Can bookmark folder pages display more lines or full verses rather than one line?

Not in the current version of Mantis. The bookmarks page is designed with small previews of the verses, so you can see more bookmarks on the page.

A future version we are working on allows you to tap to expand bookmarks to see the entire verse, though.

In addition I would like to see a global option to set the number of lines (default 1) or specify full verses. A number of related verses on some topic can be brought together and be easily read/recited/compared by scrolling one page. If they are more numerous it might be a nuisance to tap them all individually to expand them. Maybe a button could also be provided to fully expand/reduce the verses while the folder is open. Tapping could still expand or reduce individual verses.