should apply OPT first. After getting OPT approved,
submit I-485 immediately. After you submit I-485
you can still keep F1 status as long as you don't
use EAD associate with your I-485 pending status.
About 2 to 3 months before your OPT expires, apply
for EAD. You may actually get your I-485 approved
before your OPT expires. There are just too many
lawyers who don't really know what they are doing.
Having said that, you can still try to apply for OPT.
As long as you don't use EAD, you may be able to
keep your F1 status even if you have applied for
EAD.
Good luck and best wishes.