DIY Mouthwash Questions (essential oils/ETC)

I am planning on making a mouthwash and was wanting some opinions on my ingredients.
I'm also open to any suggestions/ETC.

Question 1: Would there be any complications of making a mouthwash with the ingredients listed below? I would be using all the ingredients/oils, but I haven't calculated any Tsp %'s just yet.

Question 2: Or would the below probably have adverse effects inside the mouth?
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Might seem like a huge amount of ingredients for a mouthwash, but take a look @ most toothpastes.

Ingredients:
Distilled Water
Baking Soda
Xylitol
Magnesium Chloride (MgCl)

Etc Oil Ingredients:
Clove
Comfrey
Neem
Oregano
Peppermint
Spearmint
Thyme
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A lot of the ingredients above have different effects on teeth/gums. Like remineralization and dealing with plaque/tartar/bacteria/gum issues/ETC.

Question 3: Considering that most of the ingredients above expire @ around 2+ years. Would keeping the above in the same bottle for 6months be advisable or should it be changed out sooner/later? Trying to guesstimate a shelf life with them only having their own internal preservatives. I don't know of any stability/oxidation issues just yet from any of these.