Easy way to live as Hamburg after being released is asking to become a march; you're strong enough on your one province to where Hansa will accept. This grants you annexation immunity, gives you full control over your income, and lets you have bloated FL for a period of time. You can also get marriages with nations you want to seek independence from (march perk, and Hamburg spits out as an Oligarchic Republic if I remember correctly) - this list typically includes people like Denmark and Pomerania, who would make decent short-term allies.