cat changes food, gets dirty ears, behavior changes

Question
I have two cats: Baxter (neutered male dsh, age 4; normal
personality is shy and sweet) and Snickers (spayed female dlh,
age 1, normal personality is feisty, playful and affectionate).
They generally get along very well, until the last week or so
when several cat fights have taken place. I am not positive but I
think Baxter is instigating the fights. Snickers ends up running
away and remains frightened and crabby (hissing, hitting) for
many hours post. She hisses whenever she sees Baxter now,
whereas they used to play, eat, and nap together.

Prior to all this, on August 23, the two had their
annual vaccinations. Baxter was diagnosed as obese at just over
16 pounds. We switched him to weight management dry food,
but he does still eat some regular adult cat food (Snickers eats
the regular food). Snickers had a small amount of vaginal
discharge, which has since cleared up.

Last week (the same time the cat fights started) I noticed
Baxter's ears were very dirty. The vet cleaned them with OtiCalm,
but saw no irritation of the ear canal and upon testing no extra
yeast, bacteria, or fungus in the dark brown wax. There is one
small, healing sore in one ear. Three days after the very visit his
ears were filthy again (not quite as bad but very dirty). Baxter
also lost a few ounces between vet visits.

So now, my question: could the change in food, strange
behavior, and excessive ear wax be related? Or, if Snickers still
has some kind of discharge, could this cause Baxter to want to
attack her? (We had another cat prior to Snickers, and Baxter was
mean to that cat when she returned from a prolonged vet visit
and surgery (I assume because she smelled funny) but was nice
again a few days later.) How can I keep my kitties healthy and
get them to play nice together again?

Your help s very much appreciated! Thank you!

Answer
The irritability is probably from the vet visit and change of smells.  However, there could be something outside that is bothering them as well.  

I would recommend adding RESCUE REMEDY to the water dish to help reduce anxiety and if the behavior continues, then purchse FELIWAY/Comfort Zone diffusers to plug into the house.

You can also try rubbing a towel on each of them and give it to the other.  In addition, try feeding both of them a special treat together like canned chicken or tuna.