I'm helping someone who's using Esperanto as the alien language in a story and seeing as I'm only a beginner I wanted to double check my translations

"You are pathetic!" = "Vi estas kompatinda"

"If you beg for mercy, I might give it to you." = "Se vi almozpetas mizerikordo, mi povus doni ĝin al vi."

"I would rather die." = "Mi preferus morti"

"That can be arranged!" = "Tio povas estas aranĝita" this may have been the hardest to figure out if only because I wasn't sure which 'that' to use and which ending to use for 'be'

We are not aiming for perfection just readabilty thank you!

"That can be arranged!" -
Tio povas esti aranĝita,
Oni povas aranĝi tion,
Tio estas aranĝebla

"I would rather die." = "Mi preferus morti" or Mi pli bone mortus ol ...

"If you beg for mercy, I might give it to you." - Petegu mian indulgon kaj eble vi ricevos

"You are pathetic!" - in British English this means more that you (or your actions) are more worthy of contempt rather than compassion.

Sentaŭgulo!
Vi estas nenio!
Kiel vi estas malestiminda!