Nope, this is simply the plural of אישה. Quite unnatural, but, hey, that's the way it is (the source is biblical)...
Other similar exceptions: man/people - איש/אנשים woman/(fm.)people - אישה/נשים
I can't think of other words whose plural form is not a suffix-variant of their singular, so it is a rare exception.
Tough one. I, and I think all Hebrew speakers, would say "veyeladim". At school I was taught that it should be "viladim" (possibly with a long "i"). I don't think I ever heard it like this, even in formal contexts. What I do hear in formal contexts (e.g. news in radio) is "viyeladim", or "viyladim" with a very pronounced "y".
Mind you, all these ways sound very similar, so I'm not even confident about what I hear.
"vi" before words starting with the letter "י"
"u" before words starting with the letters בומפ
"u" also before words starting with a letter with the niqqud "shwa" (two dots vertically under the letter). Bummers; in spoken Hebrew the "shwa" sounds sometimes like no vowel and sometimes like "e", depending on the letter that carries it. You might need to look it up in a dictionary.
"ve" in the rest of the cases.
Spoken Hebrew - always "ve" (sigh of relief).