In both cases, yes, you can force your opponent to do that.
For reference,
Word of Command reads:
Look at target opponent's hand and choose a card from it. You control that player until Word of Command finishes resolving. The player plays that card if able. While doing so, the player can activate mana abilities only if they're from lands he or she controls and only if mana they produce is spent to activate other mana abilities of lands he or she controls and/or play that card. If the chosen card is cast as a spell, you control the player while that spell is resolving.
Word of Command gives you control of your opponent during the casting process, which means that you make all of their game decisions for them. Word of Command limits what you can do with that control by creating additional restrictions on what decisions your opponent is allowed to make, but as long as the decisions you're making for your opponent abide by those restrictions, they're perfectly legal.
If
Gauntlet of Might is on the battlefield, it is legal for your opponent to decide to tap two Mountains, spend the red mana produced by the Mountains on
Blood Knight, and leave the mana produced by the Gauntlet floating. That decision abides by Word of Command's additional restrictions, because mana produced by each of the lands was spent to cast the spell. So it's legal to force your opponent to do that under the Word.
If your opponent controls five Swamps and
Crystal Quarry, it's legal for them to decide to tap their Swamps, spend the mana they produce to activate the Quarry, spend the {B} produced by the Quarry to cast
Duress, and leave {W}{U}{R}{G} floating. That decision also abides by Word of Command's additional restrictions, because mana produced by the Quarry was spent to cast Duress, and mana from the Swamps was spent to activate a mana ability of a land your opponent controlled. So it's also legal to force your opponent to do that under the Word.
This might feel a bit weird, but that's Word of Command for you. Apply the Oracle text, and don't worry about whether or not it “feels right”. It's never going to feel right. Word of Command is a weird old card that does weird stuff and doesn't play well with the rules. Trying to write an Oracle text for it that covers all the myriad corner cases it raises in a way that “feels right” and isn't an absurd wall of text is pretty much impossible. A little weirdness in the corners is a very small price to pay for a wording as incredibly short and elegant as the one it currently has.