You can't do those things on BRD+PLD because you can't wear Instruments and Shields, but more specifically because you can't wear instruments and PLD monsters are a hack-job of MNK ones.


BRD - With the exception of Joachim, there are no BRD NPCs/monsters that have instruments. Thus BRD monsters can only give one song each and have a limited casting range (17ish yalms) even though they'll attempt to start casting at normal casting range (20ish yalms, AI glitch that has existed since the first BRD mob).


PLD - Paladin monsters were originally a MNK hack-job. They gave them guard (the adamantoise animation you're referring to) instead of shield blocks, removed counter for the most part (except for Genbu, where they left it in probably-accidentally), changed the SP to Invincible, removed kicks (again, for the most part, Genbu can multi-attack iirc) and limited them to one swing per round. So you don't have blocks on PLD because you don't have the Guard skill that PLD mobs probably do.