The LTC4313
Ive not used it, but I[ve used similar.
The Vcc pin (8 ) is tied to 3v3,
yet the scl and sda in can be pulled up to 3v3 or 5v, dependent upon J1 position.
if they are pulled up to 5v, then I think your goign to over volt the inputs,
normally the inputs are max 0.3 volts above Vcc,
so if you want to have a variable input voltage, you need to have the Vcc variable also,
Do you want to PM us for some other comments, I think the forum is going to get a little over loaded.