With respect to stability, or more properly, recovery from capsize. Nina has one of the best hull-forms for this, her angle of vanishing stability (AVS) should be 180 degrees or very close to it, so she'd come up straight away. In contrast most modern boats have considerably lower AVSs often between 115 1nd 130 degrees, as was discovered in the 1979 Fastnet and the1998 Sydney to Hobart, with some boats staying inverted for a long time. Incidentally, the Winston Churchill's loss in the 1998 Sydney Hobart race is closer to the kind of indecent that you'd expect with a boat such as Nina ( a heavy broach followed by very quick flooding).
Nina's lines are here:
Olin Stevens refers to her as having 'a tall staysail schooner rig and a rather light hull carrying a heavy lead keel' (Desirable and Undesirable Characteristics of Offshore Yachts. Ed. Rousmaniere. pp 26)
For stability curves of various hulls Rousmaiere pp72. Nina is similar to the first one.
On storm canvas. Don Street said he'd sailed Iolaire, a 1903 yawl, into 50kts and hove to in 70kts. The traditional storm survival tactic for long keelers is to heave to until the waves are breaking close to the boat, then run off. To that end you'd expect to keep the storm sails up through the blow, and may well, as Bill Tillman did leave them to blow out on the grounds that it's preferable to risking the crew's lives in getting them down.
As for deck houses yup, Adlard Coles in the first edition of Heavy Weather Sailing has many tales of smashed deck housed and tenders swept away (the tenders seem not to have smashed the deck, merely disappeared in the night)
If you're into this stuff both books well worth reading.