Snowdrop,
While your "thank you" speech is not completely inaccurate, it is also (arguably) 100% ill-spoken (inappropriate). That, I will let you figure out for yourself. Hint: Some/most of the verbiage you have chosen/spoke is not applicable towards the "hu plig/khi tes" ceremony.
As I have already stated, whatever one says, must -- according to traditional etiquette and norms -- be relative and consistent/applicable to the "event/ceremony" at hand, or whatever is being "thanked". True, your speech, no one is going to criticize (laugh at), or tell you it is incorrect overall. But for those who know, namely the elders, they will subconsciously "giggle" internally.
Examp: Lo lus "peb tsev neeg yuav nco mus ib txhis", is (arguably) inappropriate/inapplicalbe for a "hu plig" and "khi tes" ceremony. And if you are going to say "muam phauj yawg laus", then you have to include all others as well, such as: niam hlob txiv hlob, niam ntxawm txiv ntxawm, ntxhais vauv, tub nyab etc. etc. etc.. You are best to leave it at "kwv tij neej tsa cov phooj cov ywg", as that is pretty much all inclusive, versus having to list/name every relationship (relative), where you/one will obviously miss one or two, causing those individuals to "tu siab", for being neglected/left out. That is usually what happens/will happen, in nearly every/all cases I have personally witnessed/heard about.
Again, no one is going to tell you, "You are wrong.", but it is a matter of appropriatenes s and applicability. Or simple put, professionalis m versus amateurish. Big difference. Hopefully that makes sense. And most Hmong (elders) will tell you, "Keep it short, simple, and straight to the point." That will eliminate and alleviate any unwanted mistake(s) -- unintentionall y.
Here is an example of what I normally hear throughout the community, give or take:
Ua tsaug rau nej cov (pog cov yawg) niam cov txiv, kwv tij neej tsa, cov phooj cov ywg, txhua leej txhua tus, tsis hais tus hlob tus yaus, tus laus los tus hluas. Ua nej lid tsaug, hnub nod nej sawv daws tuaj nrog pab khi ib txoj hluas rau <insert name/person> kom <insert purpose/reason, whatever the "khi tes" is for, such as sickness, graduation, or whatever> peb twb zoo siab tsis txawj tag (tshaj plaws) tsis muaj ib yam yuav paum tau. Tus tuaj pab nyiaj pab txiaj, pab dag pab zog, tuaj nrog noj nrog haus, tuaj khi ib txoj hlua los yeej yog txiaj yog ntsig tag nrho. Yog lid, peb cov kwv tij txiv tub txawm muab ib lo lus qhuav los ua nej sawv daws tsaug xwb los nej txhob tu siab nod nawb mog. Kaj ntug tag kis, xab xeeb lwm hnub, nej muaj noj muaj haus muaj kev txib, nej vam tsis txog peb cov kwv tij txiv tub los tseg. Nej vam txog los peb; peb yuav tuaj pab nej qhoc lid peb paub ua tau nod nawb. Yog lid, ua nej sawv daws tsaug nawb. (Ces "txaum yim" rau sawv daws xwb. That's it.)