The former two double a consonant, so you'd pronounce a doubled n extra long, but with plosive sounds like p, t, k, the only lengthening you can do is holding the air a bit longer before you let go - so yes, that sounds like a little pause. The latter (the dash; sorry, no kana on my phone) lengthens vowels, so yes, they sound long and smooth (hiragana does the same by just adding an extra vowel like i or u).
I am not good at phonetics, and I can't describe sounds accurately. For me っ or ッ are not a slight pause. If you say the word Pudding in Japanese way the syllables would have been crisply separated like PU - DI - NG; withっ or ッ it would be like PUD - DI - NG. The PU sound seems abruptly stopping at the ending D consonant.