I haven't had the chance to really fiddle with overclocking beyond a very small bump up to 4.7 GHz, I will update when I do. I saw some of the same leak complaints and was a bit concerned initially. There is certainly an older model of this cooler with what looks like ribbed plastic tubing, but the newer one that is being sold now and that I have are sleeved rubber hoses. I do not know if the leaking issue was more prevalent with the older style or not, but in an admittedly short period of time I have not had any issues. The hoses are relatively stiff but flexible, though I wish I could have mounted the radiator to the front of the case with the hoses at the bottom. I feel like if I had twisted the radiator around to that position, the hoses might have kinked at some point. I hope that addresses some of your questions, happy building!
The backplate does not matter much to me, I went with the cheapest 1070 I could get that wasn't red. V1 Tech does sell some nice looking after market backplates, but they are around $40.
Yeah, OC'ing is coming once I get a good feel for stock idle and load temps. I have seen many people get some good results from delidding Kaby Lake processors, I just worry about voiding the warranty on a brand new part. Maybe if I start having temp issues trying to get to 5GHz...
I see what you mean, congrats on your first build!
They pulse in and out, it just ended up like that on the pictures. You can somewhat sync them up using the Corsair Link software, but it has to stay running in the background.