“what is minimum amount of dhamma topics one needs to know in order to steadily keep progressing on lokottara path? (Is knowing basics of tillakhana, eighfold path, four truth, paticca samuppada (with basic details) enough?)”
Yes.
“AND also, you have mentioned that stream enterer has seen how to reach the nibbana, right?
what do you mean here?”
One who has Samma Ditthi has also “seen” the path to Nibbana.
– It is just that it is hard to get rid of “sanna vipallasa”.
– That means you understand how to get there. But one’s habits (gati) are pulling one toward sensory pleasures.
It is like an alcoholic who has “seen” the dangers of continued drinking but has a hard time avoiding another drink.
– So he needs to constantly keep thinking about the “adinava” of having “another drink” when the urge comes.
You need to read those posts carefully. It is mostly there.