In several of the Homebrew creating portals, there are places where you can build in options for whatever it is you are creating. However, there is no way to set it to allow you to select multiple options without creating that entire feature twice. For example, I am working on a homebrew subclass and one of its features lets the player select 2 items from a list of options at level 3, and then again at higher levels. However, to build it to allow this multi-selection I have to build that entire feature twice. This just is a lot of extra work as I will also have to do this again for the higher levels. Once I select "has options" box in the homebrew builder I should be able to then input a number that correlates to the number of options from the list the player can select. For this purpose as well, being able to copy and then edit features would be very helpful so I can repeat this feature set at the higher levels where these options become available again. 

Good news, what you are asking for is already a feature.

When you first create the options for the feature there is a field labeled "levels where options known". Just put the levels when you would be able to pick options (put the same level multiple times if they can pick more than 1 at that level).

I also suggest checking out the pinned guides in the homebrew forum for more basics on how to use the tools.