lalove

I'd say you are giving it a much more thought that the uscis does. If your i865 arrives at uscis post the 30 day period, either the reviewing officer/staff won't even care about the date or just laugh it off and update your new address in their system.
 
Of course you can but there is no need. Just send it without signature confirmation. No big deal. You'll get delivery confirmation regardless.
 
To some limited extent yes, it's in N400 instructions.
 

From form N-400:  (3) Evidence that you and your spouse have lived in marital union for at least 3 years at the time you file your Form N-400. Such evidence may include: (a) Joint bank and credit card statements; (b) Leases or mortgages; (c) Birth certificates of children; (d) Insurance policies; and (e) Internal Revenue Service (IRS)-certified copies of the income tax forms that you and your spouse filed for the past 3 years (or an IRS tax return transcript for the last 3 years).

Don't give too much attention on such minor things. You are simply reporting the uscis of your new address. If, for the sake of it, they reject it, you can send it anytime. Don't worry about 30 days reset. Some people completely forget about i865 and submit it years later. No big deal.
 
Don't staple, use paper clips.

Postmarked before the 30 day window closes is all you need.  Keep the receipt 

Never heard of an I 865 being “ rejected”. Like the beneficiary’s  AR11( change of address) it is only a notification to USCIS, not an application 

1.  Yes.
2.  Yes.  Sometimes USCIS makes mistakes.  All we can do is to fill out the forms completely and accurately.
3.  Calling USCIS would be a good idea.  No guarantee your address change will be reflected immediately in their system, but it won't hurt to check.
4.  No need to mail the form if you already filed online.
 

Which language are you referring to?  Is this the page you're looking at?  https://egov.uscis.gov/coa/addressChange.do
 
No, you won't be jailed or deported simply because of late filing of AR-11.  But like I said, if you are ok with getting your GC at either address, go ahead and file AR-11 already.  Instructions on the page linked above says to select form number "OS155A".
 

Just one I-865 with the latest address.
 
 
If you are ok with getting your GC at either address, no risk in filing the AR-11 already.  You may file the AR-11 and I-865 at the same time, but not required.  See if the online address change option via myUSCIS would be better for you.  No option for I-865 online filing, only paper-filing via mail.
 

*** Removed related thread.  Please post your related questions in this thread to keep the discussion in one place. ***
 
 
1.  The I-864 came in to force when you became an LPR, ie. the moment CBP stamped your passport when you entered the US with your immigrant visa.
2.  No, late filing of I-865 will not result in revocation of your LPR status.
 

The requirement is to notify USCIS of the address change within 10 days of your move.  But in your case, it might be safer to file the AR-11 only after you receive your plastic GC.  Your sponsor(s) also have to update their address by filing form I-865.
 

Depending on the ticket you've purchased and whether or not you have a flight rewards program, you may have a 50lb checked bag, a 70lb checked bag or a combination of bags included in your fare, or you may have none and have to pay out of pocket for each bag.  A regular old checked bag or 2 - immigration are unlikely to even think twice about it. I probably wouldn't stress too much if a couple of your things end up in your spouse's bag.  Yes, you're activating your visa, but lots of people fly south to activate it and collect the rest of their personal effects at a later date.  
 
Now, if you have 5 bags to yourself and are activating your visa, they are potentially likely to ask about the contents.  At that point, I would probably have a high level inventory of what is contained within them. Also, make sure nothing high dollar is in the checked bags.  Carry that on.  Honestly, when people fly, they aren't typically taking tons and tons into the US.  When you load a trailer full, then they are potentially worried about contraband or taxable (duty) items.  Personal items rarely fall into that category.  
 
When I originally came to the US on my work visa, the trailer of household goods had to be inventoried, but we flew (myself, 2 kids and 2 cats) with 5 hockey bags of clothing and personal effects.  The immigration guys didn't even bat and eyelash at the bags.  They were more worried that the paperwork was in order and that I had the kids' father's birth certificate to issue their L2's.  

If the transcript is available, always bring it.  Just like the wet signature on the 864, don't risk it.  
 
 Flying POE they are less likely to ask because you only have whatever baggage.  If you're paying for extra bags, that might be different and I'd probably keep those separate.  
 
You'll go through to Customs and tell them you need to activate your LPR.  They will take your passport and walk you over to a separate office.  Your spouse will likely go through immigration like usual, so you will be separated.  
 
Once in the immigration office, they will pull your case from the repository, verify the information against the visa in your passport, stamp it and send you on your way.  You'll continue through immigration like nothing ever happened.  Hopefully there aren't a bunch of people in front of you, otherwise you have to wait longer...like the interview. 
 
Caveat here is I'm referring to the process through preclearance airports.  IF your starting point doesn't have preclearance, it won't happen this way exactly.  I'd imagine there would be a connection through a preclearance airport though and at that point the above would happen, so make sure any connections have sufficient time to clear immi.  

Perfectly fine from an immigration perspective. Does you employer know you plan to do this? It can complicate things for them so I'd let them know if they do not know already. Carrying your work laptop is also perfectly fine. You'll have work authorization once you activate your visa so working from the US will be allowed.