I too use the Mogami Studio Gold balanced cables for balanced analog interconnects, and I've been very pleased with them. For a 3 foot length, they are available for $34.95 from B&H Photo Video.
Re your first question, digital cables figure to do well interconnecting analog signals, subject to the usual system dependencies that affect most cable decisions. The reverse is certainly not true, btw (interconnects designed for analog applications cannot be expected, in general, to do well in digital applications, since impedance control is essential in digital applications due to the higher frequencies which are present).
Re your last question, I don't think there is any reasonable way to adapt 75 ohm unbalanced cable to 110 ohm balanced applications. Balanced and unbalanced cables are different animals altogether.