Use the original, good MOBI. change the metadata in calibre and
resend it, do NOT reconvert it.
The title and author should be updated, but the cover will not be (only AZW3 supports updating the cover anyway).
As no conversion is done, there cannot possibly be any white pages between each page, unless they were already in the conversion
source.
Which... if you converted it as you said you did in post #3, then maybe there are.
...
Blank pages in the ebook are wrong, and if I had a book like that I would edit the book to fix it.
That is beyond many peoples' skillset though.