I would also change the oil injection lines. Find the manual so you can get the injection system bled correctly.
I use the blue urethane line available from most online pwc stores like sbt. Try and do the carb rebuilds without separating them from each other. If you do, you will have to re-sync them. Not a complicated task, just time consuming.
I would just scour ebay and such for another storage lid.
Be sure and document exactly how many turns from seat each mixture screw is, and don't get them mixed up. You will need a pop off gauge to check the needle pop off (you can get a Mikuni 0-100psi gauge off amazon or ebay), and DO NOT replace the needle spring unless the pop off is out of spec., and don't get the springs and needles mixed up. best to do one carb at a time.