Got my Baldur today! Played around with it a bit. Don't have an opinion on Bumper yet, but so far Baldur is unimpressive all around despite being the heaviest Layer in the game currently. Even in the current heaviest (?) combination possible in Beyblade Burst–Baldur Heavy Claw–It couldn't really stand up to any decent Attack Layer I put up against it (Xeno Xcalibur, Minoboros, Xcalibur). It seems to have too much recoil to work as a Defense type, low Stamina, and no Attack power.
Bite on the other hand may have some potential for pure Defense. At high RPM it has a decent amount of movement, which I think could be useful in disrupting Attack types, and because the tip is rubber it won't fly out of the stadium too easily (not that it's immovable, though). Haven't directly tested its Stamina comparison to something like Orbit or Claw, but even though it probably is lower than those two, it may have some use nevertheless.
Curious to hear from anybody else who has received theirs already!