If not, how do I get the two separate fields to appear side by side in an issue?
No, date fields all hold one single item, you'll need two of them.
As for the layout, again, no, JIRA lists them one line at a time.
Both of those could be done if you're willing to find or write an add-on to provide a dual field, and/or code to re-arrange the display
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.