I won't go to the sonic differences, as these are subjective and I do not own your components. But I can address the electrical issue involved. First, all tubes with the same pin bases may be physically substituted, but this does not mean that they can be electrically substituted. The 5V4 is certainly not a substitute for the 5AR4 though it will function in some circuits without failure. First, the voltage drop is significantly greater with the 5V4, so your circuit will have to be stable at lower voltage, second it is more fragile than the 5AR4 and you really should not directly follow the tube with more than 35-40uF of capacitance. More capacitance will probably tax the tube. You can get away with quite a bit more with the 5AR4, though good engineering practice may put the cap values in a similar range as those acceptable with a 5V4. Capacitance after the choke really doesn't matter. The substitiution may work, it may not. It may sound good and it may not.
As far as 12AU7s go, electrically they pretty much suck, that is an opinion. If I have to use them, I go for the 5963 or 6680, which are both direct substitutes. My favorite is the 7058 which was designed for automotive use, of all things. Sadly, it is not compatible with all circuits and is not a direct sub for 12AU7 in all gear.
As far as 12AU7s go, electrically they pretty much suck, that is an opinion. If I have to use them, I go for the 5963 or 6680, which are both direct substitutes. My favorite is the 7058 which was designed for automotive use, of all things. Sadly, it is not compatible with all circuits and is not a direct sub for 12AU7 in all gear.