Vauatu. 3 questions.

Dear Folks...my first Thorn Tree posting and planning my first trip to Vanuatu. Three questions if you could indulge me: 1)
My Canadian citizenship allows one month in Vanuatu. I plan to purchase the extension visa once I'm there, but when I arrive at the airport in Port Vila I will show them my onward air ticket dated 3 months after arrival and I'll tell them my intention of applying for the extension, but obviously won't actually have it. Would that be a problem?
2) I was looking on the 'net for books on Vanuatu and read reviews of a book called "Cavorting With Cannibals." I thought the title sounded a bit frivolous and comments on the book had me not buying it. One person commented on the notion, apparently found in the book, that people on Tanna ("Cavorting..." is a book about a man's recent experience) think all white people are evil. This doesn't seem to resonate with what I've read in this forum. Am I correct in assuming residents of Tanna in general don't feel that way? (Like most of us I don't like the feeling of being a thorn in someone's side).
3) re: Kava. Does anyone out there know, directly or indirectly, whether people with clinical depression, who are taking anti-depressants, might be vulnerable to serious crashes after drinking kava?

Thanks kindly for any input. I hope after some time in Vanuatu I'll be able to contribute back.

They have never actually looked at our tickets to see when you are departing.
Didnt get to Tanna but I think the Kava in Vanuatu was stronger than in other pacific Islands.
They did have Kava bars in town and the suburbs.

With regard to (2) - we stayed on Tanna for 3 nights and I never got the feeling we were not welcomed. We stayed at Evergreen Bungalows and were treated very well by all there. David, our driver and guide for the trip to Mt Yaser, was extremely friendly and even took us to meet his family and see his farm, of which he was very proud. I had occasion to visit the local hospital and had a most interesting time chatting with the locals while waiting. The ladies at the market were pleasant and we had an interesting ride back to our accommodation in an local taxi van. We passed on the visit to a "kastom village" and cannot relate how the people showcasing their culture behaved. Obviously as a tourist, you cannot really know what the local population really feels about all the outsiders who are visiting but I got the feeling that tourism was welcomed by those we met. All in all, Tanna was the highlight of our visit to Vanuatu.

Kava is a soporific and has no down side at all.

1) It could definitely be a problem.
I flew Aircalin, and they in fact made me rebook my flight out of Vanuatu even before allowing me to board my flight to Vila!

2) I found people in Tanna VERY friendly.

3) No idea about that, but Tanna kava is even stronger than kave elsewhere in Vanuatu. Maybe you should try a lighter version in Vila first?

Many thanks to those who took the time to answer. Happy Trails.