May I submit a generic letter of recommendation instead of having my reference complete the INCOSE reference form?
No. The references must use standard INCOSE reference forms.
What should I do if I do not have a reference for some of my experience?
Unfortunately, INCOSE's Certification Application Reviewers may not be able to give credit for your experience if it is not confirmed by a reference. Note that ESEPs do not need references for all of their experience, only ten years. If you cannot find enough people who know systems engineering and knew your work while you were doing it, you may need to wait a few more years to submit confirmed work experience. You may also want to start training your colleagues about systems engineering so they can recognize that you do it. References do not need to be systems engineers, they just need to know enough about systems engineering to describe it.
Do each of the references that I select need to be able to confirm my experience for the full number of years that I need to qualify for certification?
No. Each individual reference does not have to verify your experience for the entire minimum number of years of experience that you need to qualify for certification, BUT your collective set of references does need to be able to confirm your experience for the entire minimum number of years claimed by you on your application, including any additional years of experience required due to your educational status. If the collective inputs from your references do not cover the entire minimum number of years of experience needed to qualify for certification, the review committee may either turn down your application because you do not meet the minimum qualifications on verified experience or may ask you to identify and contact additional references for inputs to confirm your unverified years of experience. The latter will delay the processing of your application. For example, if your three references all confirm the same three years of your experience, you do not have the minimum number of years of verified experience. If the review committee does not turn down your application, it may request that you identify and contact at least one additional reference who can verify your experience for the additional unverified years that you have reported. Your references should provide their assessments in their own words, instead of or in addition to any "copy-paste" of information from your application.