Sufficient

means:

enough to satisfy the particular condition under discussion.

For example:

If we say:

“A person needs sufficient political standing to participate as a civic equal,”

we don't mean the person must have the same political influence as the president.

We mean the person has enough political status and opportunity to participate as a recognized equal citizen.

Relevant

means:

connected to the particular issue being examined.

For political standing, the relevant conditions might include:

• voting;
• political participation;
• access to political institutions;
• recognition of political rights.

For economic standing, different conditions become relevant:

• access to property;
• employment;
• economic opportunities;
• ability to maintain an independent livelihood.

So “sufficient” is always sufficient for what?

That question determines what counts as relevant.