[susan53]

f) He was found wandering/prowling/loitering the neighborhood. (Do prowl and loiter imply he wanted to commit a crime?)

wander = to walk around without aiming to go anywhere in particular.

prowl = to move around quietly, trying not to be noticed, as if hunting.
So yes, prowl does have a sinister feel, as if the person wanted to commit some sort of violence, and the following two examples I found highlight this. The first is from a story about a sheriff's posse hunting a murderer:
While prowling around these buildings, two of the posse recognised the voice of Gonzales
and the second from a story about a man convinced he is being stalked :
I conceived the morbid notion that the man in question was prowling round the house.

Both of these verbs can be followed immediately by a direct object, as in your example and...
I wandered art galleries and went to films
It did not care what sort of person prowled its woods
but they are much more frequently used with a following preposition or adverb. Here are some for wander :
The two children, both boys, wandered around the Australian and me for a few moments
..but wander round the shops and if, now he's gone,,,
...he can wander about you see and jumps up on the furniture ...
You can't wander along in the dark, can you?
Wander past the three superb Columns of Apollo

So here, for me, your example sounds more natural as : He was found wandering / prowling around the neighborhood.

wander also frequently collocates with nouns like mind, and memory to indicate lack of concentration : ...the boy's attention had wandered somewhat

I've talked about loiter with its meaning of "remaining in the same place" above, in the reply to (d) . The only examples that I can find which suggest that at least some movement is involved are always followed by a prepositional phrase : eg Great Expectations, Ch. 15 - As I was loitering along the High Street, looking in disconsolately...
Here loiter seems almost synonymous with wander. But this use is rarer than the other, and interestingly, most of the examples that come up are from literature of at least 50-150 years old. I did find a couple of more modern examples :
I loitered along to a special preview of the film on my lonesome.
She loitered past him, half skipping with excitement.
I loitered past my old house,
In these contexts there was no suggestion of crime and again, the verb always seemed synonymous with wander.