The overarching message for me is the question about 'what is (a) human(e)' and to 'never give up', messages that personally affected me deep- and greatly.

And as for your second question I think you are thinking too complicated, dear.

We know they have human guards and soldiers for a start, probably even after the 'Zeppelin Incident'.

We don't know about other servants next to Walter or even maids, but we do know they used to have different kind of stuff.

It's not easy to figure out what they did exactly, most likely gather information and such, like my boy Watson.

No, wait. They directly say, it's an intelligence agency.

(Can somebody read what's going on the pass?)

Here we too can assume they still have need of them after the incident.

My personal assumption is that they have fewer guards - Iscariot mentions something that could be read along those lines and also they have Seras and therefore not the need of hundreds of guards, but they still might have other kind of staff.

....