1; You can just remove the speedo and warning light section off the clocks (they do just come apart on an mc18 as well) and it's wiring without any other problems at all.
3; Yes, they all fit, be aware if you get mc28 forks you'll also need mc28 brake calipers as they bolt on differently.
4; Yes, HRC list a plug (it's just a 20mm core plug) and Tyga sell a blanking plate. Without the oil pump and bottles the bike is a lot easier to work on.
5; Tyga sell everything you need.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread