Can you spell 'ein kind' as 'eine kind'?

Answer 1

yes, but it is incorrect.

das Kind
ein Kind

no "eine" allowed. And, since Kind is a noun, it is always capitalized.

Now, with adjectives, following a definite article, they are all ending in e. Otherwise, they are inflected by gender:

das kleine Kind
ein kleines Kind

Of course, there are other changes, depending on case...