Penelope is coming back, but I don't think that many little girls go by
Penny these days.
Nell,
Nellie,
Nella,
Elle,
Ella, and
Ellie could easily be used in place of
Penny. I don't think that
Penny is an automatic.
Jim is also not very common for little boys these days, yet
James is still popular, so yes, I think it would be possible to avoid
Jim.
James is a short name, so someone named
James could go by his full name without trouble.
Matthew,
Benjamin,
Joseph,
Andrew, and
Abigail all have nicknames that are still popular, so it might be harder to avoid
Matt,
Ben,
Joe /
Joey,
Andy (or
Drew), and
Abby, but there are a lot of people who go by their full names, so I think that it would be possible for them to just go by their full names all of the time.