Yes, it is possible that an applicant that has earned their CFI-I as the initial can't teach in any aircraft until they hold the category and class on a commercial or ATP pilot certificate and flight instructor certificate. However, doesn't the certificate say "Flight Instructor - instrument airplane" or "Flight instructor - instrument helicopter" ?
61.195 (h)(2) states that the training for initial instructor certificate must be completed by a 2yr CFI.
The main topic of this LOI discusses what is considered aerobatic for the purposes of parachute requirements, although it mentions that spins are done for the purpose of the initial flight instructor certificate.
http://www.faa.gov/about/office_org...interpretations/data/interps/2012/Finagin.pdf
With those references, I'm not seeing how a initial CFI-I applicant can skip spin training, take the CFI-I practical exam and then receive it from a "junior" CFI-A. I could be wrong but I probably did 30-50 CFI spin training sessions last year for CFI applicants. Everyone one of them received training prior to the initial flight instructor check ride.