Okay, I can see what you're doing. I'm a little confused why. This seems like a potential rube goldberg machine that may exhibit some strange and unpredictable behaviour.

Maybe I'm crazy, but I much prefer to keep things as simple as possible. Pick a technology stack and use just it. Don't play mix and match games.

If java is just not working for you in lambda, due to the startup cost, is it time to consider that Java might not be the right technology at all for you to be using there?

If you're determined to stick with lambda, maybe it's time to bite-the-bullet and use Go (or something else with fast startup times).

If you're determined to stick with Java, maybe it's time to consider that maybe Lambda isn't the right solution for you? How much benefit are you really seeing vs the engineering cost and complications?