First bike a super rare, powerful sportbike that will cost $5k locally, if you can even find one? Not the best idea.
Start on the cheap end. Get a pre-2008 Ninja 250. They are a dime a dozen and easy to fix with plenty of parts available. It's small and light enough, with enough power to keep you out of trouble. If she learned that well enough, then I would spend actual money on something that rides more like a motorcycle and less like a moped. Plus, going cheap on the first bike frees up money for decent gear.
After she kicks lymphomas ass and learns the basics on the cb, why not just get her a vfr? I ride with a bunch of girls on full spec sport bikes, nobody has any problems once they know how to ride. Shoot, my mom is only 5'3" and she raced a guzzi 850 back in the 70s
I could just get her a VFR but I'm not sure she'd be happy with the weight or size of the bike. An old round headlight CBR400 might be a nice bike too. Looks great in HRC colours.
I want to try to keep her away from Cruisers. He'll only end up entering plowing competitions and getting tattoos that she'll regret when she's 45 and we'll all regret when she's 60.
Not the obvious choice for a first bike, but what a great choice. I have ridden a zxr400 once, the vfr400 will be equally easy to handle.
Sure it will cost a penny, but a special occasion calls for a special bike. I have seen a few for sale in the Netherlands, so of the uk runs dry...... ;-)