Question

will PO402 and PO401 be affected or caused by PO302

Answer 1

it is not very likely,

for P0401 and p0402 I would remove the EGR and its piping and clean it, with some wd-40 and screw driver and wire brush to remove the carbon build up.

and use brake cleaner to clean it all off.

P0302 if you have not replaced the spark plugs as a regular maintenance replace the spark plugs first, you might have a bad ignition coil or wire also.