Photo troubles.....

Since I was having trouble with the photos on the Pentax forum, I decided to post here for the day so people could see and comment on the photos!  Thanks....sorry... not sure why it didn't work from the forum but I appreciate your time to comment and help!!!!  I also posted my post below the pictures if it helps so you aren't bouncing back and forth....

Hi.  I recently purchased my first dslr a Pentax K-x and I have a couple of questions.  I have had really good results with macro photos with nice bokeh but I am struggling with portraits.  I bought my camera to learn to take professional like photos of my kids....only I'm not having good luck.  Often, they are blurry.  I've attached a couple that I have taken for you to see and offer any tips.... if I attach a photo here, can you see the exif info to look at the settings I used so you can give me pointers.  I've seen amazing photos shot with this camera but I have a lot to learn.  I took a class that moved me from auto mode to AV and so I have been playing with the settings AV and ISO but some of my outdoor photos in midday on a cloudy day take ISO 800 to 1600???  That doesn't seem right....on a outdoor day if the ISO is that high, what kind of photos will I get in a gym or inside?  

I have single point focus on, continuous focus selected,  image stabilization on,  and I've been centering my subject within the bracket in the viewfinder and yet it is sharper at other points than the middle section I have focused on.  I've been waiting for the little image stabilization light and also the focus light to come on before shooting and still not in foucs.  Not sure what's happening.  I would appreciate your help and thoughts if you have a minute to help a newbie.  (Thanks!)

Image 1:  Photo 1 is of 3 people.  ….. kits lens 18-55,  F11, 800, dark and no one really in focus…..  Do I need to go up to f13 or 16 and down on the iso then?  I guess I just can't figure out why all these photos are so dark.

Image 2:
The second image is actually taken with a 50mm 1.7 lens manual focus lens  at 5.6, auto WB, ISO 800 and yet it's so dark AND out of focus.  It was a cloudy day, but this was taken at around 2 or 3 in the afternoon and it was NOT dark....  The rocks behind him are in focus but he is way out of focus and yet I had the bracket set on his face????  It seems that if I have several feet behind my subject, my photos are more in focus, but how do I get an in focus photo when the person is next to a wall or rocks like in this case?

Image 3:  The car appears to be in focus, but not the girl?  These settings were f6.3, ISO 200, auto WB, center weighted.  Once again the car behind her is focused like above on the rocks, but not the person....  and yet I've used 2 different lenses and gotten the same results.

In all 3 photos, the time of day and lighting were very similar and yet I have 2 at ISO 800 and one at 200 and they are all darker than they should be?

Image 4 was taken and the buffalo is still a little out of focus....I think this one is because I had it set at f4, ISO 200 and probably a 7.1 would be better?  Yes/No?  I took several of him and they are all about the same.

Image 5 was a ground squirrel....locked in on him in the center of the frame and he's out of focus also.   He's at f7.1 and ISO 800....I took several of him also and they are all still slightly out of focus???

What am I doing wrong?  I would love your thoughts and ideas as this is what I purchased the camera for.

I have taken tons of macro shots with the different lenses and a few of birds and I've gotten some really good shots (some not so good either but that's to be expected)  but people are not working for me.

Would love to hear your insights!  Thanks so much!