こんな、そんな、あんな、どんな + na-adjectives

Question

How do they interact with each other? I know that depending on the part of speech these words may have/have no particle after them, but what about na-adjectives? Do these pronouns have any particle in this case?

1. こんな + 猫(noun) ＝ こんな猫
2. こんな + 高い(adjective) / 急ぐ(verb) ＝ こんなに高い / 急ぐ
3. こんな + りっぱ(な) = こんな ? りっぱ(な)

Answer 1

Both こんな and こんなに could be used, but the meanings would be different:

こんな立派な猫...
A splendid cat like this ... (of all splendid cats, I'm talking about this one)

こんな is modifying the noun.

こんなに立派な猫...
Such a splendid cat... (a cat that has this amount of splendidness)

こんなに is modifying the adjective.