I certainly have no data for this configuration, but every component will resonate at some frequency. That strap changes both the starter and the alternator. The PP alternator has the strap and it has a much shorter (mount face to pivot) bracket to the engine. Alternator certainly is one direct source of excitation but not the only one. Have seen 100+ lb hydraulic accessory pumps on a diesel flywheel housing vibrate like a couple of tuning forks breaking the housings. They were not self exciting.
All said - if B&C says they have no failures with that design, then I would accept that. Adding a link to an acceptable design will change the dynamics in an unknown way. If you check the mount torque regularly for 100 hrs and it is good, then just add the mount crack check to annual (CI) and you should be covered. Just my 2 cents.
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”