visitor visa extension for mother-in-law

[viv_mon]

I am planning to apply for visitor visa i-94 extension for my mother-in-law. Her i-94 expires in Second week of April 2014. I have few questions

1. Do I write and sign the letter explaining the reasons for extension or does she have to write/sign?
2. Do I postpone her travel and provide a copy of new return ticket or just provide the current return ticket copy which is first week of April.
3. What if we don't get the decision before her expiry and she leaves US on/or before her current expiry will this effect her future travel or her B2 visa. I read posts saying that B2 will become void once it gets denied. Is it true?

Please help

Thanks,
viv

[immihelp]

1. She.
2. New one.
3. She will be fine in that case.