The WR250R may be a bit of a stretch initially, but it will hang there with you as your skills grow. The KLR250 might be a bit more noob friendly and cheaper to aquire.
The CRF230 would be easiest to start on, but you sound like you are a bit of an aggressive person who would like a bike with some coolness factor. The CRF would be limiting if you take in really tough terrain, but good on typical trails. They have a nice easy but torquey powerband that signs off early. The stone simple CRF is also the next best thing to indestructible and it is nice and low, no worries about handing it, but you might get bored with it. Could be a good intro bike that you sell after a season.
The DRZ is cheap to aquire as well, does not weigh that much more than the 250s and it's suspension would probably be about perfect for your weight. The DRZ has good quality fully adjustable stock suspension, but needs springs for the typical 200 pound (or more) rider. DRZ power is midrange oriented and easy to handle. As a former owner (fond memories) of a DRZ, I can say they are pigs in the mud. In fairness, real mud is some of the most challenging terrain we ride and pretty much any non racing bike is a pig in the mud
The DRZ is an excellent nasty gnarly trail rock bike though. Very plush in that stuff. A visual aid for you. DRZs shine in this stuff, amazingly so for a non racing oriented bike. Was not crawling though this stuff either - 2nd gear, midrange rpm, 20 - 25 mph or so :)