Is there a way to widen the buttons in a custom dialog so my text doesn't get cut-off?

Ethan

No.

Except to use a third-party dialog plugin.

As an alternative you could exploit the New Window feature to generate your own dialog screen. Hold it on a script and wait for the user to select your own buttons.

I'll bet you could make a really neat thing if you script it well and you'll get control of the text formatting too.

That is a cool idea. is there a way to lock up the program and keep a window on top until another script is executed?

If you put the user into a looping paused script, that can only be halted by executing another script, then the dialog window can't be dismissed or hidden behind another window.