Learn English – The correct use of conversely

Sorry but your question is really too general to answer.

I'm sure some brave person will rush in where I fear to tread, but this is a complex issue: you need to go and look at an English grammar book to find all the cases. There are lots of exceptions and funny rules and overlapping cases and context dependent cases and so on and so on. You could quite easily use all three:

My mother is on the shopping centre

= e.g. My mother is standing on top of the roof of the shopping centre

My mother is at the shopping centre

= e.g. My mother has gone shopping and I am at home

My mother is in the shopping centre

= e.g. I am standing outside the shopping centre waiting for my mother.

Yes, it’s perfectly accurate. The afore in aforementioned is a comparison of time, not in location, so there’s no problem.

On the other hand, depending on context, it might or might not be advisable. Writing about the aforementioned bananas will confuse a reader if they haven’t already (and quite recently) read the mention of bananas that you’re referring to. So if you expect some participants to read your new mention of bananas before the original mention, then I’d suggest you avoid using aforementioned, even if it is technically accurate.

If you expect everybody to have read the original mention shortly before reading your new one, though, then the aforementioned bananas could a very helpful and eloquent way to jog their memories and clarify your reference.