Simple question.
Wensday
It varies between Wends-day and Wens-day. Round my way (London and Essex) people often say wens-di, with the second syllable being like the second syllable in happy. (Can’t find my usual copyable IPA chart right now).
Whens-day
I think the second syllable is the only thing in question with this word, and it’s as you describe it. I don’t think anywhere in the English-speaking world the first syllable varies in the way this poll indicates that it might, varying from /ˈwɛnz/, except as inorganic, affected hyper-correction, and even then it’s difficult, artificial and contrary to native English phonology to do so. People might think they say the second choice, but I strongly doubt it.
I don’t really understand the motivation here.
Weddensday.
Pretty close to this, swallowing the vowel after the ds a bit.
Wens day.
Wed-nes-day and I get mocked for it. Well not now, but when I was a kid.
I take that back–somewhat:
So, are you two Highland geezers?
I pronounce is winz-day (so I didn’t vote). I have also heard many of my older Ohio relatives end the days of the week in “-dee.”
For Ibanez, do you really aspirate the w?
What is the pronunciation difference between the first two options?
I didn’t know anyone pronounced it other than wens-day. Of course the’ Addam’s Family’ reinforced that belief - but I have the same non-accent that most tv shows portray as the norm.
When spelling I think of wed-nes-day and associate it with the day of nes’ wedding.
Highlands of Dublin.
I say [wɛnzdeɪ]
Try http://ipa.typeit.org/. You can type whole words out, instead of copy and pasting every letter.
I usually only have to copy a couple of letters because the others look the same in IPA or normal writing, so it’s no hassle - but that’s a handy link anyway, ty.
Wens-dee. Fairly short “ee” though, and this is the pronunciation I’ve heard most in England.
Ok for the purpose of this poll, assume the “-day” part is “-day” or “-di” or however you pronounce that part of the word.
Wendy’s day. 
*someone had to do it
Hump Day.
But normally I pronounce it “wensday,” with the “D” silent.