Ile-du-Palais may be the place you are looking for then. This island not only houses the King himself, but also a few other aristocrats and royalist politicians.

Pretty sure that covers the fourth question, since the entire planet is an entire attraction. Luxurious one mostly, so I'm quite sure a bunch of animals wouldn't draw a lot of attention. Mind you, I didn't say such cargo would pass unnoticed either.

As for Solar Engineering facilities, they're pretty much public knowledge from the charts that our people brought when they were exiled into Sirius. Doesn't include any kind of top secret place... Hence why 'secret'.

Even with this, so far Maquis have been successful at causing some noticeable damage against a few stations in New Paris... Not before having most of their ships blowing up too. With this I mean, it's a suicide mission even when we're already inside the stronghold.

So if you really aim to succeed in any propaganda endeavor, I would strongly suggest other hives that the royalist aristocracy usually swarm, such as planet Marseille in Provence or planet Nevers in Burgundy, both falling under the 'Border Worlds' category.