Spanish language Q&A Forum

I'm very confused by the explanation regarding the use of indirect and direct object pronouns with hacer + infinitive. The lesson says that indirect object pronouns are used with intransitive verbs, but shows direct object pronouns (lo) with the intransitive verb "arrodillarse". The lesson then says that direct object pronouns are used with transitive verbs, but then shows indirect object pronouns (les) with the transitive verb "pedir (pardón)". Is this a mistake, or am I misunderstanding?

I'm also confused by the difference between the example in the lesson and the example sentence further below:

The lesson teaches: 
Les ha hecho pedir perdón al profesor"
He made them apologise to the teacher.

But the examples sentences below show:

Los ha hecho pedir perdón al profesor.He made them apologise to the teacher.
I am completely confused :(

For the question "No hay muchas casas ________ el monte." meaning, there aren't many houses on the mountain, why wouldn't sobre work? If I wanted to say "there aren't many books on the table", wouldn't sobre be acceptable in that instance? 

This seems to me to be too ambiguous (or maybe too subtle) to be used in a lesson.

Gabriel no podía meter las llaves en la cerradura anoche.
Carlos couldn't put the keys in the keyhole last night.

Without additional information, it appears that it could be either way, depending on the reader’s interpretation.

Is anyone else just chipping away at the Spanish lessons here hoping that one day they will understand enough to have the courage to talk to someone in Spanish?  I'm level B1 in the lessons, but probably A2 when it comes to writing, A1 when it comes to listening and A0 when it comes to converations! 
I fully understand I won't ever be fluent unless I talk with Spanish people, but I'm level C2 at making up reasons why today just isn't the day.