hy wolfrath
regarding your first question (ID 1126 und 1655) i have some ideas.
assuming that each DC is also DNS server (unfortunately this information is not present) i would configure as primary DNS server of each of your DC´s a DNS server that is not the local one. By this you ensure that DNS is available when Directory services are starting.
All DC´s should point to the same WINS server. If WINS service is also located on one DC, the Wins configuration of this DC should point to himself.
what is the result when executing
repadmin /showreps?
You should mainly investigate the "inbound connection" part. Each incomming connection should be succesful.
Do you also have the events 5784 (Source Netlogon) just before event 1126? Do these events told that some AD sites do not have a DC of the Root-Domain?
I don't think that you have a major problem, because we also have sometimes these kind of messages (also multi-domain forest).
can you show us a AD site topology plan (which DC is located in which site)?
Kind regards