1. Here's why your sentences with 'suggest' and 'explain' are wrong:
These two verbs take two objects: a direct object and an indirect object.
In the case of 'explain', the direct object is the thing which you explain, and the person who receives the explanation is the indirect object. For example, in the active voice, you could say "Someone explained the problem to the children." 'The problem' is the direct object and 'the children' is the indirect object.
When you transform this sentence into the passive voice, the subject has to be the noun which was the DIRECT object of the active sentence ( not the indirect object). This is why the subject of the passive sentence has to be 'the problem', not the "the children" .
Active: Someone explained the problem [to the children].
Passive: The problem was explained [to the children].
Likewise with 'suggest', the direct object is the suggestion, and the person who receives the suggestion is the indirect object.
Active: Someone suggested a meeting place [to us].
Passive: A meeting place was suggested [to us].
Another way of phrasing this is with an impersonal construction with 'It' as the subject:
It was suggested [to us] that this was a good meeting place.
As you can see, the people who received the suggestions and explanations cannot be the subject of these sentences: 'we' weren't suggested - it was the meeting place that was suggested; 'the children' weren't explained - it was the problem that was explained.
2. The verb 'tell' is different. The person who is addressed can be the subject of a passive sentence using 'tell' : for example, 'Someone told me a lie' --> 'I was told a lie'.
So you can say "We were told...". This part of the sentence is fine, but the rest of the sentence order has to be affirmative rather than interrogative (this isn't a question). A possible way of rephrasing is could be "We were told where the meeting place was".