Is Friday realistic? What’s a realistic timeline? — The deadline is open to discussion before it is set.
Heads-up: this is going to slip. — A warning that the date will be missed, given before it is missed.
Can I get an extension? — A request for more time.
By end of day. By close of business Friday. — The deadline, stated to the hour.
Down to the wire. At the eleventh hour. Pull an all-nighter. — The work is finished at the last moment.