2. Verify if it's imported:
gpg --fingerprint 0x2BD5824B7F9470E6
How should I verify that it is correct ThomasV's pubkey?
There should be Key fingerprint = 6694 D8DE 7BE8 EE56 31BE D950 2BD5 824B 7F94 70E6?
Yep.
Can this signature be forged?
No you need the private key behind that public key to generate a valid sig. As far as we know only thomas has that and he hasn't been hacked. So if you trust him not to include malware and not to get hacked you can use this software. Alternatively go through the code line by line so that you don't have to trust anyone!
Can it be possible that fake public key have the same fingerprint = 6694 D8DE 7BE8 EE56 31BE D950 2BD5 824B 7F94 70E6?
Nope. Always compare the long fingerprint as above and not the shortened one (0x7F9470E6) because it may be possible to create another key pair with the same short fingerprint.