The short answer is yes but the EU citizen might be restricted in what he or she can do or where he or she can go. We have many clients in ITAR-regulated industries and they routinely hire foreign nationals.

There's a major difference between individual L-1 petitions filed with USCIS and blanket L-1 petitions/visa applications filed with U.S. Consulates abroad, with the former much more challenging than the latter. This is the case now and has been the case for many years. The main change with blanket L-1 petitions/visa applications now is the result of a policy change (put in place about 6 months ago) limiting where an applicant can apply for a visa, essentially, limiting visa applications to the applicant's country of citizenship or legal permanent residence.

Unfortunately, that's a benefits question, not an immigration one, so I'm not in a position to answer. That being said, I believe that your understanding is correct in CA.

I-130 processing has always been all over the place and can be very slow sometimes, taking 9 or even 12 months.

Yes, I am seeing N-400 processing taking longer now. And yes, you can travel internationally while your N-400 is pending.

The general feeling is that it should continue for the foreseeable future but at some point as always happens this advancement is going to slow down or even retrogress as the volume of applicants continues to increase.

Any decent immigration attorney who works with tech companies has a virtually unlimited stream of work available. I very much doubt this is the reason for the posts.

No one is asking you to read them. Feel free to ignore it. I don’t see anything wrong with YC’c immigration attorney doing an AMA on HN which is hosted by YC.

Was the EB1A petition filed with premium processing?

Yes, the processes are separate so you will need to apply for a new green card to be able to travel internationally but after you apply, you should be able to travel on your green card renewal application receipt notice (along with your expired green card).

There still are multiple visa options for founders (E-1. E-2, L-1, and O-1) and additional options if they are from certain countries (E-3, H-1B1, and TN) so they should consult with an immigration to determine the best path forward.