I think instead of going deep into the level of point-to-point comparison or surgical analysis of both the resolutions we must ponder upon the 'type' and context of both the resolutions i.e. Lahore Resolution 1940 & Objective Resolution 1949.

If we see the Magna Carta which is also known as 'The Great Charter of the liberties of England' issued in 1215 engulfs the authority practiced by the king. It is also known as 'The greatest constitutional document of all times'. So we must consider it a legislative or constitutional document.

As far as Lahore Resolution is concerned, we must know:
1. It was a demand made by a ruled community to its rulers.
2. It has nothing to do with the authority sphere of the British.
3. It was related to the protection of Muslims' rights & related to the demarcation of Muslim Numerical Majority areas of North-west & Eastern areas of India.

While we see the objective Resolution:
1. It was purely a constitutional building step of a newly born state.
2. It was related to the 'Supremacy' or 'Sovereignty' of the state.
3. It described the powers of the executive to be practiced as a trust.
4. It's a road map of law making.

So by looking at the 'type' and the context we can easily state that Objective Resolution 1949 has much more resemblance with 'The Great Charter of the liberties of England'.

Conclusion:
Objective Resolution 1949 is the Magna Carta of Pakistan. We can't term Objective Resolution 1940 as the Magna Carta of Pakistan.

Note: This is brief answer and it can be expanded by adding more points.