You need to keep the power and phone separate. 12" is the EIA/TIA recommended separation but you can probably get away with 6" and not have issue. The reason for this is to mitigate EMI (Electro Magnetic Interference). This can create a buzz sound on your phones. Never seen a phone line installed with power in a conduit so I'm not certain if this is a code issue, just not common practice. For this short distance I would install a 3/4" conduit and basic CAT3 unless you have any near future desire for a data connection. A pull string installed with this cable is wise just in case you want to add any other LV cabling (i.e. coax, control wiring, etc.) Fish tapes are nice but not necessary for a person only fishing a conduit on occasion. Any stiff wire like Romex or RG6 coax will suffice for this type of distance. Regular dish soap assists if there is any friction issue with fishing the line. Keep number of 90 deg bends to a limit of no more than 3 without a pull box.