Carrying over only some of the form field

Your first request is tricky to do correctly. I would advise against it because if you get it wrong people will be upset with you.

For example, if someone's middle name is John-Paul your script might identify it as one word and only use J as the initial, when in fact it's JP. It's best to let people decide for themselves how to write their own name.

It can be done by using slice() method.
To get four last numbers of SSN use like this in 'Custom calculation script' of
field where you want to show last four numbers:
var str = this.getField("SSN").valueAsString.slice(-4);
event.value = str;

To get first letter from middle name use slice(0,1).

Hi @Nicole23641873ej9u ,

Are you currently using any script(s)?