Hello. In future, please post a reproducible example. We do not have access to the CSV files on your machine and thus cannot replicate the graphs you've posted.
I've created some dummy data to demonstrate possible solutions to your issues.
Bar colours can be changed by passing the fill aesthetic to geom_bar(). As for your second issue, I'm guessing you have 0/1 values in the column but it's been read in as a double by read_csv(). That can be fixed by casting it to a factor before plotting.
library(tidyverse)
set.seed(42)
data <- tibble(col_chr = sample(c("YES", "NO"), size = 800, replace = TRUE))
ggplot(data, aes(x = col_chr)) +
geom_bar(aes(fill = col_chr))

data2 <- tibble(col_num = sample(c(0, 1), size = 800, replace = TRUE))
data2 %>%
mutate(col_num = as_factor(col_num)) %>%
ggplot(aes(x = col_num)) +
geom_bar()

Created on 2020-04-21 by the reprex package (v0.3.0)