Who/Whom and the/a

[lockheed]

I am well versed in English but these are some uncommon phrases I came up with and leave me somewhat puzzled which brings me here in search for clarification.

1. Who/Whom am I to cast my eyes upon

2. Who/Whom they are supposed to capture

3. If you're alone, only silence returns the/a call

4. Who/Whom am I to paint these windows for

5. 'Whose warmth they are to miss?' or 'Whose warmth are they to miss?'

I welcome any confident replies.

[5jj]

1. Who/Whom am I to cast my eyes upon?
This sounds like something from a bad swords-and-sandals film.
2. Who/Whom they are are they supposed to capture?
3. If you're alone, only silence returns the/a call.
This sounds like a bit of meaningless would-be philosophy.
4. Who/Whom am I to paint these windows for?

In all these sentences, most BrE speakers would use 'who'. Those people who chose to use 'whom' would almost certainly bring the preposition to the front of the sentence in#1 and #4:
1. Upon whom..........4. For whom...

[lockheed]

Thanks! Can you clarify no 3 whether it should be 'a' or 'the'?

[5jj]

Thanks! Can you clarify no 3 whether it should be 'a' or 'the'?

No.
As I am not sure what is meant by 'call' here, I don't know what silence is returning.

[lockheed]

Voice call, shout. Nothing to do with a phone call.
It means that if you say something, you won't hear anything back.

[5jj]

The answer is 'a call', then.