If I use Professor Turo's Scenario on one of my evolved Stage 2 Pokemon, do I put all three Pokemon cards into my hand?
Yes, all three cards count as the Pokemon. Any other cards attached would be discarded.
Source: Paradox Rift FAQ; TPCi Rules Team (2023-11-02)

Relevant cards

Note: All applicable cards may not be listed below.
SV4_171
SV4_171