Dense pack wall insulation in old Victorians and stucco homes

Here's a question for you in two parts:

We do a lot of dense pack wall insulation in these old Victorian homes (most are 70+ years old, some are around 100 years old) and we are worried about the long term effects.  Here's our concern:

• A lot of these homes were built using balloon framing which means they're drafty.  Like crazy drafty with straight shots through the walls from the attic to the crawlspace/basement.
• We are in the San Francisco Bay area which means that for the most part, these homes are subjected to pretty damp conditions for considerable portions of the year. 
• Damp conditions + drafty old homes = homes that are able to give the damp a clear exit path.

Yes, we realize that if it can get out that means it can get in - we get that.  But here's our concern:  these drafty old homes have lasted this long.  Granted, we air seal (as possible) and we install vapor barriers just as often as the dense-pack wall insulation, but if we come in and install dense pack cellulose, do we run the long term risk of moisture issues and causing unintended consequences?  Should we also be installing some form of vapor barrier in the wall?  BPI tells us that the dense-pack cellulose acts as both insulation and air sealing - but, again, what about that moisture aspect? 

The other half of this question applies to dense-pack cellulose installed in stucco homes.  Again, how concerned should we be about long term moisture issues?

We might be being a little paranoid but we just want to be thorough and do our best to really understand all of the consequences of our actions. 

Thanks!