Hey! Did you mean for flyctl ping - #4 by mobilevet to be a response to this thread by chance? It looked like you responded by email and the forum maybe misrouted your response.
If so - yes very possible. The Heroku Buildpacks confuse me quite a bit, honestly. If you’re comfortable with it, I would consider getting a basic Dockerfile setup for your project, in part because the Heroku buildpacks are super slow to deploy because they’re huge images that try to serve everyone rather than your projects’ needs. nodejs.org has a pretty good write-up for how to dockerize a Node web-app here.
In reference to not finding a node process; I did find some of the source for the Node part of the buildpack here I think and I found these variables that would make me think your node binary is somewhere in $HOME/.heroku/node/bin/.