Re: what to expect with starting solids
I found this graphic to be helpful when trying to understand the transition from breastmilk to solids. From this article.

As far as your question regarding the amount of breastmilk you would leave for your baby after a year, typically you don't have to leave any if you are still nursing 3-5 times per day your baby doesn't need it nutritionally. And in the absence of the breastmilk feedings you would expect them to eat more solids to replace it. Because they are hungrier. However if you have one of those babies that just doesn't eat a lot of solids you would probably want to continue leaving breastmilk (or replace the breastmilk with a milk alternative- cows milk, formula, etc).
Experiences around here vary, but I can tell you with my daughter she was a big solids eater and started refusing bottles of breastmilk by around 12-13 mos old. I took her cue on that and stopped pumping at that time, trusting that her varied diet of solids and continued frequent nursing at night and on weekends would meet her nutritional needs.
That's one of the great things about continuing to nurse past a year, IMO. Most toddlers are picky eaters, or at least go through picky stages. I never worried about it. I never worried whether she was eating enough dinner or whether I should offer more of the less healthy things that she liked just to get her to eat. I was able to be less concerned about her solids intake because I knew that whatever she was missing in solids, she was making up for with breast milk.
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”
--Anonymous