Reported speech question
Hello.

I created the same topic yesterday, but provided wrong information. I'm sorry. And now I want to clarify detailes.

I wanted to clarify if the following is correct :

According to rules we MUST substitute all verbs to past simple / past perfect.
We change:
present simple to past simple
past simple to past perfect
present perfect to past perfect
etc

Example:

Direct speech: “Who is the champion?”
Reported speech: She asked me who the champion was / She asked me who was the champion.
Direct speech: “What is your favourite colour?”
Reported speech: She asked me what my favourite colour was / She asked me what was my favourite colour.

So nowmy example

Direct speech: "what was the last film you saw?"
Reported speech: ?

According to rules we have to substitute "was" to present perfect, "saw" to present perfect and use direct speech construction.

She asked me what the last film I had been had seen?

Question

Reported speech question
Hello.

I created the same topic yesterday, but provided wrong information. I'm sorry. And now I want to clarify detailes.

I wanted to clarify if the following is correct :

According to rules we MUST substitute all verbs to past simple / past perfect.
We change:
present simple to past simple
past simple to past perfect 
present perfect to past perfect 
etc

Example:

Direct speech: “Who is the champion?”
Reported speech: She asked me who the champion was / She asked me who was the champion.
Direct speech: “What is your favourite colour?”
Reported speech: She asked me what my favourite colour was / She asked me what was my favourite colour.

So nowmy example

Direct speech: "what was the last film you saw?"
Reported speech: ?

According to rules we have to substitute "was" to present perfect, "saw" to present perfect and use direct speech construction.

She asked me what the last film I had been had seen?

Answer

"She asked me what the last film was that I had seen."
or "She asked me what the last film that I had seen was."

Embedded questions use statement word order.
"What is your name?" he asked me.	
=> He asked me what my name was.

More information here:
https://www.ef.com/ca/english-resources/english-grammar/question-forms-and-reported-speech/

Indirect speech backshifts verbs with some exceptions:
More information here:
https://www.ef.com/ca/english-resources/english-grammar/tense-changes-when-using-reported-speech/

Answer

First of all, in reported speech questions become statements, thus in your examples both 2nd sentences are wrong:
Reported speech: She asked me who the champion was / She asked me who was the champion.
Reported speech: She asked me what my favourite colour was / She asked me what was my favourite colour.

For the second, since when past simple converts into present perfect? In reported speech the main principle is to make one step back in tense while those 2 exist in the same spot on the timeline. One step back there will be past perfect, thus:
"She asked what the last film I had seen had been." Sounds abnormal, no one talks like that, in real life it would be something like: "She asked me about the last film I'd seen." or "She asked what last film I'd seen."