kantas's page

That's a really good question...

I'd love to see an answer about that, because i'm looking to make use of these spells much much later in a campaign i'm in...

I'm going to hazard a guess and say they do not aquire those properties, mainly because the spell doesn't state that they do. Later spells mention giving the plane properties, such as elemental properties, time properties, gravity properties.

The Greater Demiplane spell specifically states that you "add" these properties, where the Astral plane already has some of the properties present (Timeless being one of them)

Time: By default, time passes at the normal rate in your demiplane. By selecting this feature, you may make your plane have the erratic time, flowing time (half or double normal time), or timeless trait (see Time, GameMastery Guide 185).

using this information we can infer that the plane has no properties when it is initially created, and you must use the more powerful versions of the create demiplane spells to add properties to your new plane.