I'll just say my pronunciations for what I've seen in the topic, plus some extra!
I always used to pronounce Lewa as Loo-ah. Now I've changed to Lee-wah for some reason, but whatever.
I have beef with anyone who pronounces Kopaka as Ko-pack-ah. I've always pronounced it Ko-pah-kah, and the other way just sounds ridiculous.
Same with Melum nowadays. I say Meh-lum, but some people say Mal-um or Mee-lum?
Umarak I say Oo-mah-rack, but again I hear people say Oo-mar-ik.
Tahu I say Tah-hoo, but I sometimes hear Ta-you.
Onewa is a tricky one. I've always said it On-eh-wah, but some people say On-aye-wah or On-wah, or something like that.
Whenua is similar. I've always said When-oo-ah, but I've hear Whe-noo-ah.
Reidak I always said as Rey-dak.
Ackar I say Ak-ar and Strakk I say Str-ahk (but sometimes I like hearing things like "ICE AXE STR-AAK!)
Vezon I say as Vez-on, and Vezok Vez-ock.
Hakhan I say Haw-kan, Zaktan as Zahk-tan, Carapar as Ca-rup-ar.
I've heard people say Matoran as Mat-or-an, as opposed to my Mah-tor-an.
Jaller I used to say as Jall-er when I was really little, but after watching Mask of Light I always say Jah-la.
Ehrye I pronounce as Air-yay.
Kane-Ra I used to call Cane-ra, but now I got used to calling it Kah-nay-ra.
Spiriah to me is Spee-ree-ah.
Krika to me is Kree-kah.
Wow that's a lot.
Oh, bonus one:
I say Axalara T9 as Axe-all-ra, but I've hear Axel-ra and Axe-all-ah-ra.
Yay for vehicles.