1. Batch campaigns inside the Engagement are the only way to do this accurately.
Strongly would urge you to avoid Triggers except in the situations I outlined in the deck.
You are asking for an Irregular Cadence so an Engagement is likely to create too much complexity. Simplify your requirements or use a regular Smart Campaign. I outlined this in the deck.
This is tremendous! I've read it a dozen times to fully process. We are a client only operation and this appears to be the gold standard as far as I'm concerned for lead generation and the full automation world for the customer journey. I can apply the logic accordingly. Great stuff. Thank you so much!