Both of your original conversations look fine. And yes, you can combine your responses into one. Here are some possible candidates.
For example #1:
"Yes, I have already sent that email (out) today."
"Yes, I had sent that email (out) earlier today."
For example #2:
"Yes, I have already sent that email (out) yesterday."
"Yes, I had sent that email (out) yesterday."
"Yes, I had sent that email (out) last week."
"Yes, I had sent that email (out) when I was in Japan."
NOTE: In your excerpt, there is "You CANNOT use the Present Perfect with specific time expressions such as: yesterday, . . ." <== But that is not really true. Your excerpt is an overgeneralized "rule" which is not always true. There are some conditions when past-time adjuncts (such as "yesterday") can be used in a present-perfect construction. For instance, there is a counter-example in CGEL, page 144, [13.ii.a] :
- "We've already discussed it yesterday."
ASIDE: Here is a post with some info on the present perfect construction (though, unfortunately, it probably isn't directly related to your question) : What's the meaning of this present perfect sentence?
NOTE: CGEL is the 2002 reference grammar by Huddleston and Pullum et al., The Cambridge Grammar of the English Language.
The two sentence are not at all written in a similar way!
The first time when I drove was at driving school.
That is built up a bit like:
(some instance) when (I did something) was (at a specific place)
Now:
Dracula when I saw was the latest movie.
Is built up more like:
(the object I did something with) when (I did something) was (a special kind of object)
It is possible to form a sentence the way you did, with some minor changes:
Dracula, when I saw it, was the latest movie.
This sentence is very different from your example: the main clause is "Dracula was the latest movie". This was true "when I saw it". You can move that indication of time around:
When I saw it, Dracula was the latest movie.
Dracula was the latest movie when I saw it.
If latest was not meant to be used, then your sentence needs a bit more work!
Dracula when I saw was the last movie.
If you want to say that after Dracula you did not see any other movies, this sentence makes, I'm afraid, very little sense. The easiest way to say what you mean is then:
Dracula was the last movie I saw.
There is no good way to include when in that sentence. You use when to indicate a time at which something happened - but you are not saying that at all! You are not saying anything about when you saw the movie, you only want to say it was the last one you saw.
There is absolutely no way to form a sentence that looks even a little bit like your original example sentence that would simply say "Dracula was the last movie I saw". The original sentence says when something happened, and where it happened. You are not saying when you saw the movie or where you saw the movie.
You could say:
The first time when I saw Dracula was at home.
But that says two things you never mentioned :) And it does not say it was the last movie you saw!
Best Answer
In casual conversation, you don't need a complete grammatical sentence. I'd be inclined to shorten it like this:
There are a number of similar variations that might slip out as well: