Pete,

I think you are are on the right track. My advice if it will be helpful to you is:
Start with one 400 ISO B&W film and learn the exposure* and contrast aspects that fit your photographic vision.
If possible develop the film yourself. That way you are in control of the chemistry. Follow the mfg's box speed for the film and time and temperature for processing. Once you are making consistent exposures you can vary developing time to modify contrast.
If using filters for the sky and cloud definition stick to yellow and orange. You can add to your filter collection later as needed.
Cut out two "L" shaped pieces of mat board and learn to crop your images by sliding them over a work print like a frame.

The images you presented have been discussed as to the quality of the scans so I'll comment on composition which I will admit and agree are a matter of personal taste. This is how I would frame them:
#1 You cut off the person's feet. I would have shown her feet and less of the top of the structure especially on the right side where a slight sliver of sky shows. Also crop some on the right to give more importance to the figure in the image.
#2 I would crop the left side so that the letters to the left of "car park" don't show and crop the right at the end of the vertical column so the horizontal beam doesn't show.
#3 The lighting and subject are vague.
#4 I would show more of the tree (left side) and crop some of the negative space on the right as well as some of the bottom.
#5 The water line is not horizontal and the people's heads are just above the sand line that is similar in value to the heads. When in a situation like that take more frames from different positions. You can decide which one works best later.

You can also * bracket exposures when shadows and highlights are far apart. Get an 18% gray card and learn how to use it since you are most likely using the camera for metering. I'm not familiar with that camera and it's metering capabilities. Meters see the world as medium gray so metering a bright or dark subject will not give you an accurate exposure.

I hope this has been of some help. Keep shooting, its only film.

http://www.jeffreyglasser.com/