Until such time as is a use sanctioned in legal contexts, but as it adds no nuance of meaning it should be avoided in other contexts. Indeed, it should not be used in legal contexts either, except to echo the specific language of a specific law or regulation.

Use of futurive will/shall is likewise sanctioned in legal contexts, and is subject to the same strictures.

Otherwise we do not use will or would in until clauses. Anterior (later) reference is expressed with current-tense forms:

• If RT (the reference time, the time we are talking about) lies in the present or future, we use either simple present or present perfect:

  We are waiting
     are going to wait
     will wait
     intend to wait
     have decided to wait   until he finishes college ... 
                         OR until he has finished college ...
  

• If RT lies in the past we use either simple past or past perfect:

  We were waiting
     were going to wait
     would wait
     intended to wait
     decided to wait    
     had decided to wait    until he finished college ...
                         OR until he had finished college ...
  

Thus, we would say

I will wait until you have contemplated all the implications of your action.

Since your question was about the tense and not the whole construction, I'll address that: this tense is called the "conditional perfect" and it is incorrect in this sentence.

Normally we use it when there is a condition stated (protasis) and a conclusion (apodosis), usually in an if-clause, but this is often left off when it's obvious.

For example:

If I knew you were in town, I would have invited you over for dinner.

In your sentence, there is no protasis, so the use of "would have" is confusing. I would have used the simple past:

We decided to wait until such time as he finished college, before asking him to take over our law firm.

As others have stated, that is rather wordy and clumsy, so a better sentence would read:

We decided to wait until he finished college, before asking him to take over our law firm.

The phrase Until such time as is unnecessarily long and too much wording, and it's recommended that it should be avoided.

The process will continues until such time as some results come out.

Instead of the above quoted sentence we should write the following -

The process will continue until some results come out.

But essentially both of the quoted sentences bear the same meaning.

Now coming to your sentence, I will avoid until such time as, so in your sentence I will replace the phrase with simply until

Not only that in place of would have it's correct to write would in this case.

We decided to wait until he(our son) would finish college, before asking him to take over our law firm.

would have will be best suited in hypothetical situations.

And your last sentence with "will have" doesn't seem right to me. Because we use will have when we look back something from a specific time, with a sense of something happened certainly. Though the sense of certainty is to the speaker, it might not be true in actuality.

I will call him at 8 PM. By then he will have returned home.

The match will have started by now.