Trying to get v(t) for discharging RLC battery
My first question is, if I do the following, are all the voltages in
  my differential equations the same voltage?


Yes, there is just one voltage in this circuit, the voltage across the parallel connected elements.

$$v_R = v_L = v_C = V $$


  Second off, if this does all solve for the same voltage, then it is
  problematic because I'm getting a complex value


The solutions to this homogeneous 2nd order linear differential equation are of the form:

$$Ae^{s_1t} + Be^{s_2t}$$

where \$s_1\$ and \$s_2\$ are the roots of the quadratic equation:

$$s^2 + \dfrac{1}{RC}s + \dfrac{1}{LC} = 0 $$

Now, there are three possibilities:


There are two distinct real roots - this is the overdamped case
There are two identical real roots - this is the critically damped
case
There are two complex conjugate roots - this is the underdamped
case


Can you take it from here?

Hint: recall Euler's formula:  \$e^{st} =e^{\alpha t}(\cos\omega t + j\sin\omega t\$) where \$s = \alpha + j \omega\$