New to plotly and need clarification with a scatter plot

Hello

I am totally new to plotly and rstudio. I was able to successfully run and got scatter plot but I have two questions:

First: What does the following statements means after I run the code:

No trace type specified:
Based on info supplied, a ‘scatter’ trace seems appropriate.
Read more about this trace type -> https://plot.ly/r/reference/#scatter
Warning messages:
1: Ignoring 74 observations
2: line.width does not currently support multiple values.
3: line.width does not currently support multiple values.
4: In RColorBrewer::brewer.pal(N, “Set2”) :
minimal value for n is 3, returning requested palette with 3 different levels

5: In RColorBrewer::brewer.pal(N, “Set2”) :
minimal value for n is 3, returning requested palette with 3 different levels

Second question, the size of my markers are determined by a continous variable, how may I incease the size of the markers keepign the proportion of the values of the variable?

Here is the code I am running:

 fig <- plot_ly(final, x=~agebuilding, y=~violationstotal, mode= "markers", color = ~INdexrehabless6, size = ~totalvalue)
 fig <- fig %>% layout(title = 'styled Scatter',
                  yaxis = list (zeroline = FALSE),
                  xaxis = list (zeroline = FALSE))
 fig