Hi Ah-bin and niuc.
Yes, great topic. You've managed to "feel" the subtle meaning of these particles quite well, Ah-bin.
My usage is similar to Niuc's, with some differences.
Niuc, how come you're writing ho
r*? It that your convention of hO*, the open-o? Or have Bagan Hokkien speakers acquired an -r- sound

.
I have two 啊:
- "a1" (mid-high level) 唔是汝个啊1: "It's not yours!" (Re-emphasizing something which should be known or obvious to both speaker and listener, perhaps with some indignation on the part of the speaker - "m-si lu-e a1, lu an-cuaN teh lai iong." (= "It's not yours, how could you take it and use it!")
- "a3/7" (low level) 唔是汝个啊3/7: "It's not yours?" (Expressing surprise, "I thought it was!")
I have two 啦:
- "la2" (high, perhaps slightly falling) 唔是汝个啦2: "So, it's not yours!" (with some explanation preceding this phrase, like: "wa ca-huiN hO lu cap-khO-gin, so hit-pun cheh m-si lu e la!" (= "I gave you 10 dollars yesterday, (so I've more or less covered the cost of the book), so it's not yours (any more)". Perhaps similar to the one Ah-bin gives as "lo". It's used to show that the phrase is the
conclusion which can be drawn from some logical thought process, without the listener necessarily being expected to have drawn the conclusion in the past, but where the listener is now being invited to see the obviousness of that conclusion.
- "la3/7" (low level) 唔是汝个啦3/7: "(It should be obvious to you that / I've reminded you a couple of times in the past already that) it's not yours." (With perhaps a hint of impatience or annoyance on the part of the speaker).
I have a high, slightly falling tone for 咩, and it's definitely "mE" not "me". When I was on holiday in KL last December, I noticed that the friend I was visiting also uses "mE", not "me" for this particle, even though he's not a speaker of non-Penang Hokkien. I think this "mE" is quite widespread in Malaysian Hokkien, even among speakers who don't have "E" in other words. 唔是汝个咩2? "Isn't it yours? I have thought all along that it was!" (I.e. expressing surprise that something is or isn't the case). Note that it's not just only for 'negative' sentences; it can also be used for 'positive' sentences: "lu be khi mE?" (= "Are you going? I thought you couldn't stand those sorts of holidays! / I thought you couldn't stand that guy, who's also going!").
As a phrase-
final particle, I only have "ha(h)N3/7" and "hO(h)N3/7" (I tend to drop or not have an -h- in both). They're particles affirming or emphasising the truth of what was said. I think the Buddhist monk who gives those lectures available on the internet uses these a lot. These seem to be to be interchangable, not much difference in meaning. They can also be used stand-alone as "yes", with "ha(h)N3/7" being perhaps more common as a stand-alone "yes".
But I also have "haN5" and "hON5" (low rising tone), and here the usage is different.
- haN5: cannot be used phrase finally, just as an independent exclamation of surprise or doubt, only at the beginning of a phrase. "haN5? i mana u kau lui thang be an-nE tua keng e chu" (= "Huh? Where would he have enough money to buy such a big house?"). It can be used preceding phrases having the second 啊 above: "haN5, 唔是汝个啊3/7?" (= "Huh? Isn't it yours? I thought it was"). As far as I can see, in usage it matches exactly English "huh?".
- hON5: can only be used phrase finally, to ask for confirmation of something the speaker expects the listener to know to be true. "Lu ma-cai be khi ka lang, hON5?" (= "You're coming with us tomorrow, aren't you? (that's what we've all assumed all along / you said you would two weeks ago / etc).")
Hope this helps. I'll cover "ni" in a later reply.