jbuck -- great to see you diving in with such enthusiasm. As jatrax says, your opinion is the one that counts here. But of course that won't stop the rest of us from deluging you with opinions.
From our exchange on the critique forum and from the goals you list here, I think you'll want at least one fast prime in the mix. You were already after thin DOF effects for closeup work, and in portraiture you're likely to want to get even faster, as in f/2 or better. (Faster because with portraiture you won't want such a close subject distance as you had with the ornament shot, because this would give a distorted perspective, huge nose etc., and with a longer subject distance the DOF is thicker.) 50mm is quite a versatile focal length for general portraiture on your K-r, and fast 50mm lenses are plentiful. Indeed, you'll see the phrase "fast 50" quite a lot around here. So I'd say a fast 50 is an obvious choice.
You can't go wrong with any of the Pentax 50mm f/1.4 or f/1.7 variants. I think the f/1.4 is the better choice because it's faster, and also because the bokeh tends to be smoother (the 1.4s have 8 aperture blades vs. 6 for the 1.7s). There are plenty of third-party makes too. A Pentax-M 50/1.4 will usually sell for $80-$150 depending on condition and seller; that's the cheapest of the Pentax 50/1.4s. Manual focus and "green button" metering in manual mode. (See
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html and
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/60081-usage-green-button.html.) Add another $20-$30 to get the A-series version; this gets you aperture control from the camera and use of all exposure modes. The F- and FA-series versions will run $250-$350 (the FA is still in production so can be purchased new or used) and give you autofocus. I love my M 50/1.4 but it does take just a little more time and care to use well, and the extra couple of seconds can mean missing some opportunities.
Use the kit lenses and after you've taken a few hundred shots take note of what focal lengths you use most. This will give you a better idea of whether or not you need new gear. For example if you find yourself shooting at 18mm frequently, maybe you'll want something wider. Or if you shoot around 30mm a lot, maybe a prime in that range (what we call the "normal" focal length for a camera with an APS-C sensor).
When you see references to "A50/1.4" and so on, that means Pentax K-mount lenses. The first article linked above should give more info. Full name of that lens is "SMC Pentax-A 1:1.4 50mm".