During game set up, you can set the starting relations you have with each race. Reset this to either "random" or "unknown" (whichever is a choice, it's been a while).
Ships defend one at a time until the defender builds an Orbital Fleet Manager on that planet (old versions of game) or the newer building (name escapes me at the moment), which only requires one building to let fleets defend empire-wide.
You would have to define overvalue for terraforming. They're valuable techs, so unless it's *really* out of hand it shouldn't be a problem. I haven't noticed it as one, anyway.
The ship saves will require someone a bit more knowledgeable.