Work Experience (6 month stint) - Reference?

Hello, I have finished all of the exams however work experience is the remaining step. I currently have about 3 years at my current job, which qualifies, however I have these 2 shorter stints:

  • 6 month contract (HR said they will be a reference (but only to confirm date/title - not performance), however did not have a good relationship with boss, he did not reply to my emails)

  • 6 month job that I was laid off from due to clients falling through and no work (50% chance it will be a reference).-after this, I went back to my current job (that I have been in for 3 years)

From what I see, I need 3 references, however I do not see a place to link each reference to each job, however I want to know what you guys think.

Is it best to simply finish the 48 months / 4 years at my current job and apply at that point? Either way, I would be under 30 when I have met the 4 year requirement.