Синонимы слова

I agree that there is no single universal word to apply in all situations described,but among endless list of "approximations", I would
suggest

1) наглый
2) нахрапистый
3) нахальный
4) беззастенчивый
5) напористый
6) настойчивый

where shades of sense are changing gradually from 1) rather negative to 6) rather positive.

Nouns exist also "в ассортименте":
наглец, нахал, бесстыдник, but they all pertain to "negative edge of spectrum"