I cut a few of my dip tubes but used a tubing cutter and then a file to remove any burr on the dip tube. I've had no issues but I'd expect bending the dip tube would work equally well.
Unsure what you mean by 'in to in connection'... To transfer between kegs I just have a short jumper which connects 'out' to 'out' (ie - the dip tubes on both kegs).
I've fermented a few dozen batches in kegs and do a closed transfer and haven't run into any issues or problems. Like others mentioned I just use a picnic tap to get rid of the crud before I transfer, was surprised how quickly I get to clear beer when I do a good cold crash.
I've tried a few different methods for dry hopping when brewing in kegs but haven't settled on my favorite method. Right now my preference is to put the hops in the serving keg using something like this: http://stainlessbrewing.com/Dry-Hopper-with-twist-cap-_p_155.html
Thing I haven't tried is the spunding valve but am quite curious and will likely end up getting a one before long.