Google typically shows the first 50 to 60 characters of a title. Keep it under 60 and put the most important keyword near the start.
150 to 160 characters. Google may show more on mobile, but plan for the shorter length and put the call-to-action or key benefit early.
No. Google rewrites descriptions about 60% of the time if it thinks the page content better matches the search query. Write a good description anyway — it's your best shot at the click.