Disputes about the Beis Hamikdash

Daf Yomi is now learning Zevachim and the Gemara there is starting to get into disputes about the Beis Hamikdash. So far we have a few (Zevachim 53-59):

1. Was there a base around the whole Mizbeach or only on 2 sides? 
2. Was the whole Mizbeach fully in the north or half in the North or fully in the South?
3. Where was the כיור?
4. What was the size of the מזבח הנחשת?

Here are some diagrams with the various opinions about the location of the mizbeach and kiyor.

Here is a diagram showing the dispute about the size of the מזבח הנחשת.

We see clearly that the Tannaim who lived not long after the Beis Hamikdash was destroyed were missing important information about the Beis Hamikdash and simply did not the details of how the Beis Hamikdash was laid out. If they didn't know this basic information what else didn't they know?