help! F1/485pending, how to fill out 156 for parents visa applic

Dear all,
I am a student, planning to graduate this May. I came to US with F-1 visa and maintained my status until last year when I filed my 485 based on marriage to a US citizen. Right now, school still treats me as F-1 because my 485 is pending.
I am planning to invite my parents for my graduation. I have three questions:
1. For my parents's visa application, do I need to provide both I-20 and I-485 receipt? I dont want to hide the fact that I applied for GC, but I dont want to volunteer additional information either.
2. Do I need to mention my hu*****and in the invitation letter or does he need to invite my parents with me as well?
3. for the 156 form, there is a question:
are any of the following persons in the U.S. or do they have US legal permanent residentce or US citizen? Mark yes or NO and indicate the person's status in the US.

should I fill it out as :
SON studying

or

SON studying/applied for US legal permanent residence?


thanks in advance