Sign Languages and Deaf community in Hawaiʻi.

Hi everyone!

I realize that this sub is not generally for advice about visiting Hawaiʻi, but I hope you'll excuse me due to the specific cultural knowledge I'm looking for. I am Deaf, and I'm doing some research into Hawaiʻian sign language. My sweetheart grew up in Hawaiʻi (They aren't Hawaiʻian but they lived there from birth to ~16 I believe) and we hope to visit friends and family there one day. I'm familiar with the history of the country, and I was looking into the sign language and Deaf culture there. I was saddened to learn that the native sign, which I was hoping to study up on some basic signs from so I could communicate properly a bit in emergencies or anything, was heavily impacted by the seizing of the area by colonizers. If I understand right, ASL is now pretty commonly used over native sign. So now I have ~questions~ for any other Deaf people who live in Hawaiʻi or people in Hawaiʻi in general.

Is how I understand the language situation true? If so, which specific signs/language would it be best for me to learn before visiting? Do signs and language use vary by island? What're the cultural niche's of Hawaiʻian sign and ASL in Hawaiʻi? Also, a question from my sweetheart, when finger spelling what is the sign for the ʻokina?

Any help at all would be so beneficial!!!! (Cross Posting to r/Deaf and r/VisitingHawaii as well since I feel they may have more specific cultural knowledge and visitinghawaii is kinda about this in a way!)