I still feed my DS at 16 months and plan to keep doing it until he self-weans (although I hope that is between 2 -3 years! 
Breastfeeding after brushing teeth shouldn't be a problem as research has shown that breast milk is protective against cavities. Some dentists don't agree, though, and ours suggested wiping his teeth after a feed 
When you say you are confused as to how to fit it all in, what do you mean? are there more things in your life now that makes breastfeeding difficult? If you are out and about, perhaps your DS dislike mine - he doesn't tend to ask for milk when we are out of the house.
Another suggestion is the "don't offer don't refuse" approach, which can help cut down on feeds. It is common to continue to feed in the evening and the morning at this age (or more, if you are my son!)
As for cows milk, we were recommended to treat cows milk as if it is a snack and offer it when you might offer a breastfeed during the day (like the middle two feeds in the day) along with a snack. But my little guy hates cows milk, so I have never tried it. He loves breastfeeding, so we will just keep feeding on request for now.
Hope this helps