LP8340 able to tolerate voltage when not powered up?

" ... Can the LP8340 linear regulator tolerate 3.3V applied to its Vout pin ..."

No.

The LP8340 has a PMOS pass element with a body diode that will allow reverse current to flow from Vout back to to Vin if Vout is higher than approx Vin+0.3V.

This is not a recomended operating condition.

Thanks! 

Would it be ok to parallel the outputs of several LP8340 devices through 4.7 Kohm resistors?

One resistor on each of the outputs to a common point?

Yes.

Not exactly.  Up to eight of the LP8340 each providing 3.3V to pull-up resistors on an I2C bus with 8 address lines. 

Anything on this?

Not 100% sure of what you are trying to accomplish.

If this is simple, and is the only pull-up to the bus, then it should be OK. Remember to keep the minimum Cout and the minimum load to GND for each output.

If you are trying to do more than what is describbe here, then probably NOT going to work very well.