Can the sizes of these items be increased?
 

2650x1600 resolution.

I'm wondering if these items can be made larger (1-4)?

They can, but it'd apply to all resolutions. There's no way for the UI XML to scale elements based on the screen resolution (in fact I'm not sure there's any way for the UI to find the screen size). I'd have to literally write a second version of Profit with the sizes of every element in the XML increased.