"The letters from ISO Latin-2, Latin-3, Latin-4, Latin-5 that didn't also appear in Latin-1 were combined together into Unicode Latin Extended A Block, which extends from U+0100 to U+017F ... in addition to the letters .... the designers of Unicode added other related letters that are used in the various European languages". (from Unicode Demystified, page 220 ...)
Seems for me suprising, that Hawaiian characters are also included in this block ?
But perhaps this link (or the whole site) http://www.olelo.hawaii.edu/enehana/winkbd.php
may be interesting for you ?
Conclusion after a short overview: get the right font, manage all your text in unicode (or utf8) and solve your input problems (keyboard) - but the site describes several solutions.