Javelin as melee vs ranged weapon

Two successful Command spells on the same target, what happens next round?

Should multiclass 3rd casters round up or down?

Do swashbuckler rogues get to add their dexterity modifier to offhand weapon attacks while two weapon fighting?

Can a spell like Maximilian’s Earthen Grasp or Telekinesis be Twinned?

Does something that makes disadvantage on ability checks also impact skill checks?