I plan on buying tickets on an ÖBB Railjet train that departs from Munich. Currently only full-fare (Flexpreis) tickets are available and I can buy either on the DB or ÖBB website for the same price. If I buy on the ÖBB website, it gives me an option to select seats where on the DB site it does not. This is for first class. So I am thinking of buying on the ÖBB site, but the DB site mentions that we would get DB Lounge access with a Flexpreis ticket. We will be at the station early, so lounge access would be nice. My questions:

1) Will a full-fare ÖBB first class ticket give me DB lounge access in Munich?
2) If I buy on the DB site, I assume I will get lounge access, but is there a way to select seats on the ÖBB site after booking a ticket on the DB site?
3) I believe there is a 'premium' section of the DB Lounge where food & drinks are free - is this true? Would my ticket give me access?

Thanks!