The bare minimum that you’d need is based on what you plan to use it for. This will determine your channel size. I have a channel that’s roughly 300k sats that I use just for zapping

And have no issues. The channel size needed may be dictated by your channel partners rather than what your intention is. The first action you take on Alby Hub is to open a channel. This can be with one of their Lightning providers, an independent node, or your node if you more than one. Maybe research this at the Alby Hub site. Se below for a better idea and how I run my Hub.

When you send your sats to Alby Hub, they will be used to open a channel and then you can spend them.

I don’t think you can go directly from Alby Hub to cold storage. I think this would have to be done via some other wallet.

If self hosted and only one node, you won’t earn sats since the transaction either starts or stops at your address. If you were running two nodes, the Alby Hubs only entry/exit point what the other node (using it for liquidity) you would earn sats on every transaction on the liquidity node.

Can’t answer about the ip address.