The capsules will dissolve, I promise. Fairly quickly too. Midwives do it all the time to induce labour. I used to be very uneasy about douching too (I don't even like tampons), however having two children has relieved me of the aversion.
All of the things listed can be taken orally as well (except the boric acid :> ). Oregano, thyme, calendula, and peppermint oil and teas, the yogurt and kefir, the collodial silver, the vinegars, etc. However, it will take longer as you'll need to address the bowels to truly get rid of the problem.