Reciting بسم الله الرحمن الرحيم when continuing to the next surah in Taraweeh Salaah

Q: If someone is leading a congregation, for example Taraweeh. Does the imam need to say بسم الله الرحمن الرحيم after he finishes a surah and decides to continue? For example, if the Imam just finished Surah Baqarah and wants to continue to Al-Imran, does he stop after finishing and continue or does the Imam recite Tasmiyah and then continue to Al-Imran? Please clarify me on this.

Partnership in a business

Q: I have started a new business for which I need some funds. I do not want to take a loan that involves interest. I have found an investor but he wants some kind of profit. I really really need the fund for my business so how do we proceed in a halal manner?

Talking loudly in front of one's parents

Q: In my house, we (me and my siblings) have debated on many issues and this sort of debate is normal for us and it is often how we come to a decision. While debating we tend to raise our voices but this is also normal for us (everyone is our house tends to talk loud). We mean no disrespect to our mom by it. From what I know, my mom does not get offended by this and actively takes part in these debates. Is this sort of a thing a sin or considered disrespecting our parents?