Concurrent Filing I-130/I-485

[katskill]

I have a question on the technicalities of the I-130/I-485 filings for a person that's currently visiting. I have filed this before, but havent noticed some of the finer details. My wife's brother (citizen) wants to apply for GC for his parents. They are currently tourists here till middle of June. He's not sure if 1 month is enough time for them to get the receipt notice enabling them to stay.
Now what I want to know is,
1) Which receipt notice is necessary for them to keep staying past their I-94 date? Is it the receipt for I-130 or for I-485?
2) When you do concurrent filing, do both I-130 and I-485 have to go in same packet? Can you file I-485 a week after the I-130?
3) One thing he's planning is to file I-130, and then if he gets the receipt in a couple weeks, then he will file the I-485. That way, even if it gets delayed, they can go back. And he can file I-485 next time they come to US.
4)How long does it take these days to get a receipt notice? If he files May15, will it be safe to assume that he will get a receipt by June 15?

[immihelp]

1. I-485.
2. It can be either way. However, if you are filing I-485 separately, the filing address is different.
3. I don't why they would want to do that. Even after filing I-485, they can go back and come back with Advance Parole. If they are not planning to stay in the US immediately after filing I-130, why wait for I-485 until they come next time? Why not go for consular processing?
4. Timing vary all the time. Check http://www.immihelp.com/processing-times/

[katskill]

Thanks for the response.
4) The timings on the link are processing times. Im talking about time to get a receipt notice. Isnt that what matters when it comes to making sure they dont overstay their I-94? Where would I find that?
5) Which service center would this case belong to? Would it be Vermon (filing from CT) or the National Service Center?