Strange cave

[Bottesini]

If someone uses strange cave to play a stage one fossil as a basic and you evolve it to a stage 2 is it still considered a stage 2 or is it now a stage one card.

 

[Big Daddy Snorlax]

It is still a Stage 2. You go by the text on then card.

BDS

 

[PokePop]

There are two things that you check.
First, does it have any Pokemon cards under it? If not, it's Basic and you don't look at the Stage printed on it. This applies to a Stage 2 put into play by something like Archie.
If there is a Pokemon card (or Fossil) under it, then it's "Evolved".

If it's Evolved, then you look at the Stage printed on the card. Stage 2 printed on the card, it's an Evolved Stage 2.