Nay, probable. An inverter can, very roughly speaking, take a slice of current anywhere it likes on the voltage wave, so yes, it’s almost certain to appear reactive.
That I doubt. Those are expensive and heavy - what you’re seeing is much more likely due to the electronics taking current that looks inductive due to the phase angle. (Unless, as I suspect some do, it’s trying to clean up distortion on the mains and injecting current at a point on the wave that has that same effect.)
That’s exactly correct. You don’t even have to do the sum, ct1[or whatever].powerFactor is already available to you, multiply it by 1000 (to make it an integer) and add it to the PayloadTX struct “emontx”, and in emonHub (if you’re using that), add it to the Node parameters with a scale factor of 0.001 (to turn it back into a decimal with 3 digits precision).
But emonLib calculates the power factor from the definition, so it won’t give you the sign - leading or lagging. To do that, you’d need to do something like the 3-phase sketch does and delay the voltage wave, but by 90°.
Look at the “Use in North America” page. There are plenty of larger CT’s listed there. The YHDC one doesn’t even need you to change the burden resistor.
I suspect that’s 30 W consumption to keep it alive overnight.
Shame on you 
As far as I know, that’s correct. Very many “energy” monitors only measure current, and guess voltage, power factor, or both, and call the result “Watts” - most likely because it’s all but impossible with a battery-powered transmitter and CT to do otherwise, and in any case most of the time it’s good enough for the average technically illiterate consumer to whom VA and power factor, and even the difference between power and energy, is meaningless.
Yes there is, but not at the same resolution as dBC’s. Robin Emley has produced sketches that do just that, all listed at Robin's Mk2 Code variants and associated tools. | Archived Forum
I think you want “RawSamplesTool_4ss_2”
