<VV> head to block bolts

[pete]

When I removed the head,I had some difficulty taking the nuts off these bolts. The rear driver's side was the worse one. I finally cut the nut off with a dremmel tool.Also,some of the bolts pulled out and others are seized. I have purchased new bolts,but have decided to replace only the ones that came out or are damaged;i.e. thread ruined. The problem now is how do I removed these seized bolts SAFELY?
  Also any advice on how to lower the engine to get the head back on? As you can now tell,I removed the head with the engine in place. Will also replace motor mount,harmonic balancer,push rod tubes,o rings,exhaust donuts and both exhaust logs. Open to all helpful suggestions,as this is my first attempt at this and sure do not want to mess it up.
    Thanks;   Pete [use to be "rookie"]