No great experience to give you a definitive answer. I think you're just
about spot-on with your concerns, but I would look at this as a risk
management exercise. On a one-off hand assembled board, absolutely do it.
On a high volume production product, heck no. As is usually the case in
most things, reality probably lies somewhere between the extremes.

As to #1, I think that a properly designed footprint should have each pad
be a net neutral force during reflow - i.e. center of pad=3D=3Dcenter of pi=
n
contact area. As such, missing a few pads on one side should remain net
neutral.
As to #2, I wouldn't be overly concerned unless you're working on something
expected to survive "high acceleration events". (think artillery shell)
you're only talking about an 8% reduction in contacts. I think you'd see a
bigger difference than that in the variance between lead and lead-free
solder.
In low volume setting, if you're greatly concerned about #3 - just cut them
off at time of assembly.

-Denny
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