Hmmm, If you bought Hobie 16 shrouds as a replacement for a new boat ... the new shrouds should be about 2 inches shorter than the old shrouds. I could measure my shrouds if this would help you out?! The new shrouds should allow for more than a healthy mast rake even without further shortening of the shrouds. Actually you should run in to trouble with the length of the forestay (should be too short) Regarding question 1... I would not do any DIY crimping on anything that holds the mast up. Not sure if I would let the local boat shop do it ... Masts are expensive so are heads.
Question 2 ... sorry I have 6:1 Harken blocks. Question 3 ... not sure if I got that one... Do you refere to mastrake and jib cut? If this is the case ... kind of difficult... probabely means you would end up getting a new jib. Kind of difficult to compensate for the modification to the jib any other way. You might want to consider not raking to the absoulute max...

Patrick