It makes sense to first check the incoming emails for viruses. If emails containing viruses are reject, processing of a message can stop here.
The spam evaluation shall happen before aegee-mitler is run. The idea is that the anti-spam software inserts in headers the result of the spam-evaluation, the Sieve module of aegee-milter evaluates the inserted headers and based on them takes decisions.
It is recommened to run aegee-milter after the DMARC evaluation was performed. aegee-milter can redirect messages and applying the DMARC policy (reject) after a message failing DMARC was redirected makes things more complicated.