Re: shodan shinsa vs. 1st kyu
I've hear it said of our organisation that 3rd kyu is the toughest test (relative to your ability at the time of testing, of course) until nidan.
And it is all relative. People tend to put so much emphasis on shodan that one typically wouldn't be allowed to test until it's known that they will almost certainly pass. With kyu grades this may not be so much the case.