Yepp. The D5 can be substituted. Alphacool is offering the same distroplate also without their own D5.
Well. I still don't know. I didn't start the d5 not the system yet. Till now i'm building on it. And i won't be able to say how noisy that distroplate will be with the supported holders. I did construct a special nounting frame where the plate is in the sidepanel implemented. If that is too loud i will use pads betrween the mounting and the side panel of the case. Right now i have the mounting frame directly layn and screwed at the side panel on the other side i directly screwed the panel and the distroplate. That could be louder. If so i will lay (silencer) pads between the self designed frame and the sidepanel and also in the gap between panel and distroplate. That distroplate has connectors for a radiator and th building area is intended to be in front of a radiator. But it my case... I do not pay that amount to have the plate nearby invisible or having other significantly advantages..
That metal inserts are looking good if one can see them. One only has to realize that those metal inserts are also screwed to that acrylic distroplate. Alphacool also delivers a few plugs. For a normal (only CPU) loop one has to buy two more. But i took others equal to the rest. The delivered plugs wer nickel (shiny) but i have satin titanium matte all over.
I have a EKWB D5 installed at my actual rig. The case is open because the air flow is messy at that Lian Li O112D (XL ROG...). The mounted fans (EKL) are much louder than the pump.