Flying to Fiji with Air New Zealand

I'm flying to Fiji with Air New Zealand later this year, and I'm
changing planes at Los Angeles.

I've never changed planes en-route before, and I wondered if someone
could explain the process to me... Will I have to collect my
suitcases, check in again and go through all the security checks
again?

I have one hour and 15 minutes between arriving at LA and departing to
Fiji. I'm worried that this isn't enough time. When visiting Boston
last year, it took over an hour just to get through the securtiy
checks...

Any tips would be greatfully received. Cathy