Simple question, where's safe and where's not safe to store things in Severin Manor?

According to the uesp, everything is safe. I would just be cautious at around the mannequins.

Why the mannequins? I know they move around an' all, as do all of them, but are you saying they might reset and lose anything I put on them?

I have stored stuff in all of the downstairs rooms and nothing has disappeared, even when I left Solsthiem for a while. Not sure about the barrels upstairs though.

I'm not too bothered by the barrels. I'm more interested in the weapons racks, plaques, chests, display cases and mannequins.

M'aiq's mannequins act like a regular NPC sometimes.

All of Severin Manor is safe.