The FTDI datasheet has a number of examples of supply configurations. You should look closely at them for ideas. Most reasonable configurations are listed there. Your configuration may work, but I'd be very very careful testing it.
What precisely you're trying to do, I don't fully understand. It seems that you want to power the FTDI only through USB. This is fine, but as you've noted in the comment you should not power VCCIO without VCC. This is the case with most chips, usually. The solution depends on what exactly you're trying to optimise for.
If the consumption of the FTDI when USB isn't around is a problem, then you would want to turn it off. However, turning off the FTDI when it's hooked to the uC lines directly is not a great idea. I have done this, but it requires ensuring that the uC pins are configured as input and tristated with no pull up. You can have the FTDI turned off and the uC on more safely by using a level translating buffer like the SN74LVC1T45. A resistor between +5USB and ground, in your case provided by the resistor network on reset, will disable the buffer when the USB is disconnected. I have done this also, and it works like a charm. Detecting this (your pin B) is going to slightly more complicated, though.
The resistor network on reset is a good way to go, and to be honest, is probably your best bet if consumption is not your demon. This would be a self powered configuration, and would power your FTDI using the uC supply. The reset resistor divider still uses +5USB, but nothing else does. In the absence of a USB connection, the device is held in reset and consumes very low power. This is really enough for most applications. It makes detection of the USB power also possible using your reset resistor divider as you included in your schematic, which is safe. Since everything is powered up. You should avoid plugging in USB when the uC is turned off, though, or atleast ensure the series resistor is high enough to avoid powering the uC through your USB detection line.