When playing solitaire, is there still a limit of 5 Developments as per "the normal rules above" (I presume not since 5 Developments is an end-game trigger, and the solo variant always lasts 10 rounds)?
No. You can complete all of the developments in the solitaire game, if you are so inclined and able.
Thnx David - so the 1 Development per turn limit "normal rule" wouldn't apply either?
The one DV per turn rule still applies to the solitaire game. But you play 10 fixed turns and can acquire, therefore, up to 10 DVs. And all 7 Monuments may be built as well, if you are able.