… I have found some interesting shapes in articulations across different fonts …

If I understand you correctly, you are talking about font characters - right?

… Is there a way of importing them into the noteheads dialog? …

I do not know of a “noteheads dialog”.

Could you explain the steps to get to the “noteheads dialog”?

… Alternately is there a way of mixing the noteheads of different fonts within the one stave? …

Indeed there are ways.

But we need more info than just “within the one stave”.

- In different measures of the same staff?

- On different beats of the same measure?

- On the very same beat?

The better we understand, the better we can help.