Where did you play basketball at?
This is okay. The at is not necessary, but it is normal in some people's dialects. You might want to avoid it, unless you want to sound dialectal. This advice applies to writing, not just speaking.
Where did you go to?
This is commonly used. For example: in the sense of trying to find a lost pet or even a lost object: Now where did you go to? Or Where did you get to? or Where did you go/run off to? It is a rearrangement of "To where did you do?", which sounds rather stuffy.
What did you do this for?
This is natural and common. 'What for' or 'for what' can have the same meaning as 'why', so this is fine and means the same as "Why did you do this?"
Which boy did you play games with?
is rearranged from the rather stuffy
With which boy did you play games?
As for
Where did you break in to?
Grammar Girl's explanation, in this case, is fine.
Where are you from?
is perfectly normal English. It would be weird and unusual to say or hear "From where are you?"
You want to know why Where are you from? is okay? This is one of those answers that amounts to because this is how we say it. Please note that in informal language it is acceptable to end a sentence in a preposition.
You can find both the instances where on/in is used. And yes, both can be used. Nevertheless, in my humble opinion, the preposition 'on' is more preferred when the platform is online.
I have 399 registered people on my FB page.
But, ...
I have 23 students in my group or circle.
So, if the book club is online, I'd prefer using 'on.'
Again, both are okay and can be used but when it's on the Internet or digital devices, 'on' is what I may prefer.
Best Answer
Idiomatically, there is no preposition there, and your grammar book is correct. We say "problems verb-ing" or "trouble verb-ing" much more than we use with or in or about or anything else, although those constructions are used sometimes too.
You can think of "problems finding our house" as "problems while in the process of finding our house". "Problems with finding our house" is perfectly understandable, but less idiomatic. "Problems about finding our house" doesn't quite make sense - about usually means something like "regarding the subject of"; you might say "Here is a math problem about calculating sales taxes", but "problems about finding our house" sounds like puzzles that you have to solve to find our house.