How can you say this with a straight face? A $100M company takes years to build. You think in 2020, if these guys walk away from the table with $400k each for ~20 hours of work they did in 2015, that's reasonable? That grant would be bigger than anything any subsequent engineer would earn, and it's beyond dubious to think the contribution of this guy -- who's patting himself on the back for figuring out a CRM schema -- is worth more than the guy who stays for 4 years and actually helps brings the product to maturity and exit.
In reality, each of these guys did at most $1,000 of work. If you wanted to express it as equity, they're off by at least one decimal place. Them coming away in 2020 with ~$20-40k is a much more reasonable valuation of their contribution.