Hey,
VA loan and fha 203k rehab loan is two different tools you can use depending on the property. VA inspectors are pretty picky. My first duplex was new construction on a VA loan and even that got kicked back for issues that needed to be corrected. I would research what each loan would look like. Who knows you might find a great rehab with promising numbers.
Like others have stated you can use the VA loan twice. It's been awhile since I've looked into this. But from what I remember you basically have a entailment amount. So you buy home one for 200k and that wraps of 200k of your 400k dollar entitlement. Your next property is 250k. Which is 50k more then what you have left and would need to come up with 20% of that 50k. Also from my sit down with a broker a few years ago your living situation just needs to change. Like new job and need to relocate, or kids and need more room, or kids moving out and you need less room. But who knows things could of changed.
And remember just because you can put zero down doesn't mean you should. Always check your numbers and make sure the investment is right and not force it because you can do zero down.