Same conduit is alright.
It would be ideal if the circuits pairs were each twisted (spiraled hot + neutral) for mimimized noise induction between them. However it's done, so don't worry about that. If ground conductors are separate, then they should each be spiraled in the opposite direction around the circuit pairs.
Metal conduit is fine; it is good for RFI shielding.
The 'best' conductor is a controversial question: many varying opinions there. #10 Awg. solid THHN is good. A number of upgrade wire types are also available but some are quite expensive; I can't say if that is worthwhile or not.
Your house ground is the same for everything. Multiple grounds locations can cause major problems with loops, and especially regarding lightning issues.
The audio loads are better off on the opposite phase from your motors if possible. But if they're 240V you have no choice.
It would be ideal if the circuits pairs were each twisted (spiraled hot + neutral) for mimimized noise induction between them. However it's done, so don't worry about that. If ground conductors are separate, then they should each be spiraled in the opposite direction around the circuit pairs.
Metal conduit is fine; it is good for RFI shielding.
The 'best' conductor is a controversial question: many varying opinions there. #10 Awg. solid THHN is good. A number of upgrade wire types are also available but some are quite expensive; I can't say if that is worthwhile or not.
Your house ground is the same for everything. Multiple grounds locations can cause major problems with loops, and especially regarding lightning issues.
The audio loads are better off on the opposite phase from your motors if possible. But if they're 240V you have no choice.