1) Our neighbors have a pet dog. Whenever the Moazzan gives Azaan, the dog starts howling as if he is crying. Can I ask you what is the reason behind that and what can we do?

It is narrated from Abu Hurairah (ra) that Rasulullah (Sallallaaahu Álayhi Wasallam) said, "When the Adhan is pronounced Satan takes to his heels and passes wind with noise during his flight in order not to hear the Adhan. When the Adhan is completed he comes back, and again takes this heels when the Iqama is pronounced; and after its completion he returns again till he whispers into the hearts of the person and makes him remember things which he does not recall to his mind before the Salaat and that causes hem to forget how much he has prayed."

In another Hadith it is said,

"When you hear the barking of the dogs at night seek refuge in Allah from the devil." They see the devils and bark. In the night the devils spread about every where.

It could be possible the dog sees the Satan run at Azaan time and barks.

2) Yes, it is permissible to listen to audio lectures.

3) The word "haula" means power, might, and strength: ability.

And Allah Ta’ala knows best

References

§ Bukhari vol. 1 pg. 357

§ A Gift for Women: by Mufti Mohammad Aashiq Elahi Buland Shehri, pg. 428

§ Al-Mawrid

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai