The stack trace bit is hard. For local development, ideally there's some fancy service discovery where your local service can hit a development instance of another service if you don't have a version running locally.
For me, it boils down to "this is absolutely doable but I'd still rather have as few services as possible while still maintaining useful levels of separation" - at least for the primary business services. Having a bunch of microservice like things serving pure infrastructure roles can be much cooler depending on your situation.
$100/service. Is that top level service? To cover a 100 endpoints at one service each is going to be 10k/mo?
I believe $100/service is top level service, not endpoint. But really not sure.