There is technically no minimum but nodes might have their own line and force close anyone below it. Try checking amboss or reaching out to the node runner if you can.

Check out https://lightningnetwork.plus/swaps for inbound and outbound Liquidity. Also, you can check on the explore option on this site, which will list all the public nodes and you can do you research on each node by checking their profile out and there are links to Amboss and other resources, which will give you more information about each node, if the node operator has any limitations listed. Good luck.