I think it’s ambiguous grammatically, but I read “one of these” as one of the much bigger ones discussed in the article. “One of those” for me would have been a reference to the previous sent me, i.e. to a Hiroshima/Nagasaki sized one.
Can you really say those were dropped in anger? From what I’ve read they were dropped to avoid the cost to American lives a ground invasion would bring. Several warnings were given to Japanese leadership to avoid a bad outcome, which were not heeded. The first bomb itself did not result in a surrender either. To me the motivation was less about anger and more about practicality.
"In anger" in these contexts usually means "trying to kill people", as opposed to "in testing or training". It does not mean that the people who did so were angry at the time.
Would have been easy to drop one on, say, Tokyo bay if you wanted intimidation. But the US also wanted reliable data on the effects to buildings and people.
I really wouldn't be so sure. Even after destruction of Hiroshima and Nagasaki, the Japanese military still opposed surrender, in fact the day before the Emperor was supposed to announce it there was an unsuccesful coup attempt to prevent it.
So no, I don't think just detonating the bombs "harmlessly" would have have had the same effect. In fact hitting a target just slightly off the mark(like Tokyo Bay) would have been presented as American incompetence and failure of aiming.
Were the atomic bombs really all that different from the systematic fire bombing of Japanese cities?
I think what got Japan to surrender was a certain common sense in the emperor and some of the elite that a final last stand wouldn't do them much good. Especially not with the Soviets joining in.