Currently,not allowed thai Fishing boats go to Burma bank at the moment. It's very complicated! Burma banks was the Myanmar Sea. If you want to go to the Burma banks, you have to get a special permit and also visas.
Yes , Ranong-Kawthaung border checkpoint was open for tourists and also for Visa-run tourists. I live in Kawthaung and if you want to know about more information Contact me on Facebook or WhatsApp+959250886927
Border bounce is a kind of entry permit, we call EP. EP permit you can stay 2 weeks at the border town where the town you border bounced but you are not allowed further outside of the town. Yes, to the Myeik Islands accessible from the Kawthaung-Ranong border checkpoint because Kawthaung is the main gateway into the Mergui Archipelago. But you need E-visa or embassy visa to go visit the Mergui islands.