In my opinion the most important step to take is creating a dv master that already meets festival specs, which usually includes zero black or 7.5 black for 30 seconds, color bars and tone for a minute followed by 30 seconds of identical black to what you laid before the color bars and tone, and then picture starts on time-code 1:00:00:00.
The audio levels of your movie should match closely to the zero tone reference you are laying down with the color bars, which for digital is somewhere between -24 to -12. (probably -16 is the safest bet) It's almost pointless however to put audio tone down on the color bars if it doesn't accurately reflect the audio levels of your movie.
Now you can take your mini-dv master EXACTLY AS IT IS and have it dubbed from serial digital to digital betacam as long as you have gone to a qualified duplicator how uses the expensive dv decks. Ask for everything to be matched identically as it is being dubbed, meaning color bars and tone, video levels AND time-code all are transferred to match the master you gave them. There should be no extra charge for this either. However, it is just as possible, and more likely, that your final edit master is not consistent all the way through and it might just be a waste of money to make the digital betacam copy too early in the process.
Once you do have a digital betacam master made, you may want to consider getting a betacam sp submaster made from the digital betacam. Betacam SP tapes are easier to view since more betacam sp's exist out there and since the betacam sp copy came directly from the digibeta copy it lets you know exactly how your digital betacam looks. It's much less expensive to have the betacam sp evaluated for problems than the digibeta master. If you discover any problems, then you might have to fix them on your time-line and repeat the entire process.
Some festivals show betacam sp and not digital betacam because betacam sp decks cost four times less than a digital betacam deck. I don't think there will be a noticeable difference between digi beta and betacam sp IF the original camera format was mini-dv.