And here are the answers.
There is a crossfade at the beginning and end of the loop. Never noticed a click therefore.
A spillover is not possible, as the looper records delay and reverb on location "post", rather than playing back into delay and reverb. You wil have a spillover when you set location to pre.
Thanks for your interest! 
Sometimes, the transition between end and start of the loop is a bit rough, that's not the looper's fault. The possibility to set the crossfade just a tiny bit longer could help smoothing these transitions when your step on the record button was a little bit off. A slightly longer crossfade helps with quick editing of recorded parts (cutting/pasting) and I think it would help me with my shortcomings in the same way.
Haven't noticed a click with the looper. What you're looking for is quantisation, and there are pluses and minuses to that kind of situation. With quantisation, you'll never be able to record in odd times, that's what I've noticed with most loopers. And if you aren't recording on a click, even if you have quantise, there will be silence at the end of your loop
With a longer fade time you will likely harm the first pick attack.
Haven't noticed a click with the looper. What you're looking for is quantisation
Speaking for me at least, I know the difference and while switchable quantisation would make implementing the loops easier (in some places), it's not what I mean and what I need at the moment.
Crossfading works indepently from quantisation and serves well in DAWs to create smooth transitions between glued audio elements.
The options given in the DAW to find a good compromise between a fluid transition and not killing the first pick attack might be overkill for the looper in the KPA, I see that.
Then again, CK has found great and simple solutions for other things.
I'm fully aware of the fact that this probably isn't a priority for most users though.
