US Citizen mother's I-130 pending, visiting US on B1

[committed]

Hello,

I am a US citizen and filed for my mother's I-130 about 4 months ago. I am hoping that it will be approved maximum in next 1.5  months as per dates. Because of my personal health issue I am planning to call my mother to stay with me ( she already has visitor visa). She had visited US 4-5 years ago and returned within 5 months. 

Q1. If she comes, will she be allowed entry at POE as her I-130 is pending?

Q2. In case if her I-130 gets approved by the time she comes, will they send her back that your immigration petition is approved and they can't let her in on B1( non-immigrant intent). So in that case I should call her quickly before I-130 approval comes?

Q3. I think once her I-130 is approved before her entry expires, I will be able to file for her I-485 during her stay here in US so that she doesn't have to go back.

PS: - I am in my 3rd month of pregnancy. Can she tell at POE about my situation that she is here to support me mentally? 

Thanks a lot for advice/suggestion.