4 moth old w/ blood stools w/ increased Eosinophils

My 4.5 month old baby boy started having bloody stools about 3 months ago. The blood is bright red and is fairly scant. The amount of blood varies between every stool. Sometimes the blood is absent to the naked eye. Often the blood will be mixed with mucous. Sometimes there is just mucous without the blood. It is typically very watery and only becomes thicker after he has had some rice cereal.

When I presented to my pediatrician once I first noticed the blood, a C&S was run and came back negative for any bacteria or parasites. Next to consider was allergies. Aaron consumes only breastmilk. We add Tri-Vi-Sol to the breastmilk. We do not use formula. Since our 2nd visit about 2 months ago, my wife eliminated milk products from her diet. A month ago, she has eliminated soy from her diet as well. We were convinced it was the soy as the amount of blood continued to decrease after she stopped consuming it. All that changed after his 4 month immunizations. A few days after the shots, the blood became much more apparent again and with every meal. Not knowing what else to do, my wife has now also cut out all nuts, chocolate and eggs as of 4 weeks ago. The blood has decreased again but still appears in small amounts every other diaper or so.

Aaron is a happy little guy white no significant changes in discomfort, increase in crying, or other ADLs or apparent s/s. His spit ups after meals have decreased – He did vomit forcefully about a month ago when we trying introducing formula (Similac Soy), otherwise he has not vomited since he was a 1 month old.  

We recently introduced rice cereal reconstituted with my wife’s own breast milk. He is fine eating it with no change in the amount of blood in his stools.

The stool consistency is usually fairly soft with occasional diarrhea. The color ranges form bright yellow to dark green. He usually stools during each one of his day meals.  

I would like to know if we can’t seem to r/o cretin foods, what should we be considering?
Running the C&S again? R/o GER? Ulcer?

We just had a CBC done on 10/9:
WBC 10.3
RBC 4.39
HTC 32.4
MCV 74
RDW, RBC 13.8
PLTS 482
Neutrophils 26%
Lymphocytes 5%
Monos 6%
Eosinophils 16% (this is very high above the 4% norm)
Basophils 2%
Neutrophils Absolute 2.7

And has a Stool Culture 10/11:
Clostridium Difficile Toxin A+B, Stool, EIA – Negative for C-Diff
Stool Culture – No Salmonella, Shigella, or Campylobacter Isolated
No E.Coli 0157:H7 Isolated

If we are unable to stop the blood in the stools, any future side effects?  What could the increased Eosinophils mean? Our doctor said this was a concern.
We also have a dog in the house. Could this be related?