Sorry to be a bother but wonder if someone can give me the correct pronunciation and form for my grandkids given names...and how I would address them..

Michael...that would be A Mhicael"... ceart?

How about Jennifer .."A ?

and one more, Vincent....A ?

The first mentioned is the onl one to carry his gr-gr-grandfather Irish name, though... :<{

GRMA

When you're addressing someone, you put "a" before the name and you add an h after some consonants (and sometimes an i after the last consonant).

Micheál > a Mhicheáil! (or in some places: a Mhichíl!).
roughly pronounced "VIH-hyahl" (hy is the sound you have in England English "huge" or "Hugh") or "VIH-heel".

Jennifer > a Jennifer! (maybe there is some Irish "equivalent" of Jennifer but I don't remember it so wait for other answers)

Vincent > a Uinsinn! roughly pronounced "INN-shinn" but with nn's pronounced as in "new" (ny-sound).

"and sometimes an i after the last consonant). "

Before the last one. Just a typo, Jeannette

Bearn a chara,I never before knew that Uinsin = Vincent!GRMA.
Micheal = a Mhichil here in Munster.

I believe Jennifer is originally an Irish name = Findabair in Old Irish.She is in the Tain so it has to be pretty old.There is an Old Welsh cognomen - Gwyn - then a suffix meaning head,but I can't remember it!Anyhow Findabair means Fairhead/hair.In the French retellings of the Arthur myths she becomes Guinevere,anglice:Jennifer.I mo thuarim fein anyway.Graves 'The White Goddess' is a good source.

Bearn > oh yeah, sorry! before the last consonant !

Jennifer is an Anglicised form of Gwenhwyfar (a Welsh name that means "white ghost"). Gwen =white (Irish fionn).
The Irish cognate is Fionnabhair in Modern Irish and Findabair in Old Irish, as you said. However the name Jennifer comes from the Welsh form, I think, not from the Irish one.
Guinevere may be Old French, 'cause it is Guenièvre in Modern French.

However the name Jennifer comes from the Welsh form, I think, not from the Irish one.

From the Cornish form, actually. There's apparently some question as to whether it's truly a Cornish cognate of Gwynhwyfar, but I'm not up on the details.

Some source suggested Sinéad for Jenny... which I think is a shortened form of Jennifer anyway... looked this up because I've felt interested in a girl with a related name, LOL... Sinéad was suggested for Jeanette and its forms too, BTW.

But if there is an older Irish word that corresponds to the origin of Jennifer, then that might be good. And as Fionnabhair might not be a very common name nowadays, that would add some curiosity.

Approximately /Finnowr/ ???

Firstly, Jenny is an old knickname for Jane.
"Sinéad is an Irish form of the French and English diminutives Jonet, Janeta and Jennet." (Gaelic Personal Names, 1981).
Why is there this interest in translating names? Most of the names fashionably current in the USA aren't really "translatable" at any rate.
Why not
"Conas atá tú, a Jennifer?" Or, if Jennifer prefers, substitute an actual Irish name. Most Jennifers probably wouldn't like being called something like Fennore at any rate.
Get on with learning the language and skip the symbolism.

"Why is there this interest in translating names? Most of the names fashionably current in the USA aren't really "translatable" at any rate."

.....Because grandkids and their names are important to grandmothers....and historical names from the Irish or Dutch. German, Italian, or etc. are important to generate interest and inform.... and to attempt to link up ancestors and family history.

It just so happens that those grandkids names are names of their ancestors. I don't intend to call Jennifer anything but her lovely name "Jennifer"...just wanted to give her some background info about names and how they evolve. Who knows maybe when she grows up she will become intersted in things Irish.

Personally have never been interested in the latest americanized popular kids' names....but that doesn't have any involvement to my original question.