Т - К construction: ... то, как...

It was my understanding that Russian uses these in corresponding pairs
То,что --- pronoun, pronoun
Тогда, когда --- adverb, adverb
Так, как
там, где

Yesterday I realized I couldn't convey "...about how they..." in Russian, trying things like "о так, как", and knowing that was wrong. I moved on, confused, at the time, but I just saw what seems to be the missing key here. I had believed that it would be a little conceptually strange to mix them but I guess it's actually crucial and incredibley useful.

По-рууски: Подобно тому, как это говорят русские.

"То, как" seems to be verified

1) Ive only seen this example, so I want to make sure this really is a thing, and moreover, what do other combinations come out as?

pronoun, adverb
то, когда ?
то, где ?

Я рассказал ему о том, когда она умерла.

I also have to ask, why am I considering то so special. I suppose it is the only one that is an actual pronoun, and declines, except for что. 2) This leads me to ask,what would these phrases mean in context, or are they at all valid:

adverb, pronoun
тогда, что/чего/etc.
там, что/чего/etc.

Шли мы туда, о чём бабушка говорила.

(trying not to confused что the conjunction with что the relative pronoun, the latter being the topic of interest here)

These things are hard to uncover and understand as an English native because we, in most casual speech, bundled and package both halves into one question word, and throw one preposition to the end. Learning how to reverse this process is fundamental for learning Russian I feel.

Я рассказал ему о том, когда она умерла. The 2 haves are not connected and I guess you wanted to "glue" them. In this state it means:

I told him about that, when she died. Note: that the sentence doesn't make much sense without proper context, more specifically what том refers to.

Шли мы туда, о чём бабушка говорила.

Again 2 different halves that are not connected in any way and you can't even fit this sentence in some specific context. If I were to connect these two, I'd say:

Шли мы в то место, о котором говорила бабушка.

Huh....Well shoot... Strange.
I guess all I have left to ask is why "... тому, как..." works in that context. How much can that be bent, and why is it the only one that works, while the theoretically similar ones don't?

I was going to explain that in my post above but this stuff is so hard to wrap your head around, espesially if you don't study Russian grammar in depth, that I just couldn't think up a good enough explanation at the time. Anyway, I think I might have come up with something cohesive now. You see, this whole thing with these "connectors" is just grammar. Say:

То, как он говорил, разозлило меня.

I intentionally put a subordinate clause right into the middle of the independent clause as I think it can show things more clearly. Let's think about "то" and its role in the independent clause.

То разозлило меня

1. То is the subject of this clause.
2. То is also a demonstrative pronoun, so it's semantic meaning is not clearly defined, instead it "absorbs" the meaning of the thing or idea it points at.
3. Now what is "как он говорил"? It's exactly what "то" points at.
4. Can "как он говорил" be a subject? No, it can't! So this is where this "то" comes in. Its purpose is to assume the role of the missing subject and glue the two sentences properly. Without it these two clauses are nothing but two different sentences. I personally like to call this a "blank" subject, object or sometimes a pointer (like туда).

This is why то, как works, as the pronoun то can be easily defined by как...

I hope this makes sense.

"Туда" as a such placeholder (in joint of two phrases) can be paired with "куда" and "где":
"Мы шли туда, куда бабушка сказала (нам идти)."
"Мы шли туда, где было нужное нам место (по рассказу бабушки)."
I cannot remember any other pairs for it right now. Anything else sounds strange.