If the water is clear, and you are just going after pathogens, all you need is a UV or ozone unit. The ozone is probably cheaper to run, the UV puts nothing in the water. None of the other filters mentioned will get rid of pathogens unless it is one of those stand-alone units, with which I am not familiar.
I believe ozone will dissipate naturally if it sits for a bit. Chlorine needs to have some contact time between injection and consumption and would need to be filtered out with a charcoal filter.
You can get your water tested for coliform bacteria. A lab can do it and there are some DIY kits online. With the cattle being a periodic contamination source, this may not be helpful.
When you install your system, you should sterilize you piping system that will handle the potable water after the filter (or just the whole system). Use unscented bleach (google for concentration) and let it sit for 12 hours or so. Then run the water until you can't smell chlorine.
One source of contamination that is many times overlooked is the hot water supply. It should be treated as potable water. If you keep the tank below 140 F it is a big breeding reactor for things like Legionnaires. A shower can kill you. For those about to take to their keyboards to tell me I am crazy about the hot water - it has happened. Documented.