Hey ittiger, thanks for these questions.

1. No minimum, you can install it on your desktop and try yourself. We recommend opening channel of minimum 250,000 sats for it to be usable, cost of such is ~5,000 sats.

2. When opening a channel, your bitcoin become spendable capacity on your lightning channel - meaning now you can use them over the Lightning Network. Opening channels incurs fees - onchain transaction fee for opening, reserve for closing and a fee to LSP if you are using them. Alby does not charge any fees.

3. Yes you can earn with routing, and set fees per each public channel. however the Hub interface is not optimized for advanced routing configurations

4. Of course it's possible. When you close channel, spending balance falls to your onchain balance. You Alby Hub after all is also a bitcoin wallet, you can see onchain balance on the interface, can withdraw sats from there and you are the only owner to keys to that wallet.

There are also swap services out there that enable exchange between onchain sats and lightning sats for a small fee (sometimes it's cheaper than channel closure)

5. Alby Hub loads some data from remote servers (like bitcoin price), and using NWC requires using our relay. All can be configured to use your own, you can also unlink Alby Account and not use NWC to limit any information sent to Alby, but that will limit some services.