What are the current ferry booking and travel requirements from Surat Thani to Koh Pha Ngan or Koh Samui for travelers using Thaipass?

1) What is the condition for a person who is running on Thaipass (been here since 25th Feb), to book a ferry from Surat Thani to Koh Pha Ngan/ Samui?

2) According to the number one it requires a RT PCR, is it still true ?

Additional questions:

3) is this the only official website to book a ferry to those islands? If I purchase the ticket from Surat Thani trainstation -> Koh Pha Ngan, it means I can depart from the train station even though it's a ferry ticket?

4) Can I travel from Koh Pha Ngan to Koh Samui easily, once I got myself in either one?

Thanks everyone.