Potential Seller Involvement Beyond 12 Mos (SBA constraints)

I saw a recent post here on seller involvement post-close. Situation here is a bit more nuanced, and I’d appreciate input from anyone who may have dealt with this. I’m in discussions to buy a small, niche OEM business. Founder is a highly technical engineer who built a strong product with an impressive installed base over 15+ yrs, but has intentionally kept the business very lean. He’s retiring because he and his family have little interest in continuing to run the business. He's indicated, though, that he might agree to do product development under certain conditions (unknown what they are as of now). As part of the acquisition, there are several unfinished projects/prototypes: 5 are iterations of existing products with new functionality for specific edge use cases 1 is a new product in an adjacent niche (potentially more energy efficient than what’s currently on the market) Daily time constraints have prevented him from completing these (he handles quoting, procurement, inventory, admin, etc.), not the lack of technical skills. The core business is stable and generates recurring sales revenue from spare parts, so these prototypes would be upside and aren’t required for my base case. The underlying product category is also relatively mature (long equipment lifecycle and incremental innovation rather than rapid obsolescence), so ongoing R&D isn’t needed to maintain the existing revenue base. My challenge: Post-close, I would ideally like: 3–6 mo transition period for knowledge transfer Continued involvement that focuses purely on completing the development of these unfinished products as I believe there is value here However, I understand SBA guidance limits the seller being onboard to less than 12 mos, and only as a 1099. Questions- 1) How have others structured continued seller involvement beyond 12 mos without creating SBA compliance issues? 2) Is it feasible to: 2a) Separate “transition support” from “independent R&D consulting” after 12 mos? 2b) Or would SBA still view this as continued seller involvement? 3) Have lenders pushed back on situations where the seller remains technically critical (although not operationally involved)? 4) Any best practices for: 4a) De-risking key man dependency in parallel 4b) While still capturing the value of unfinished product development I’d appreciate any experiences or ideas, especially from those who either have or considered navigating this with SBA lenders. Thank you.