Answer 1: If you don't reply to your ticket in 15-days from the day it was issued, the court will send paperwork to the Washington Department of Licensing indicating you failed to respond. Even though you do not have a license in Washington, your privileges to drive in Washington could be suspended. If that happens, and you a caught driving in the state, you can be arrested for driving on a suspended license, which is a criminal offense. You make a reply by either paying the ticket in-full or requesting a mitigation hearing or a contested hearing.
Answer 2: Yes, under the rules for traffic court, if you hire a lawyer to handle your ticket, your lawyer attends court and you do not have to. Your lawyer can examine the ticket and see if there are any defense to the alleged violation and either get the ticket dismissed or reduced to a less expensive violation. If you plan to hire counsel to assist you, do so before the 15-day reply period is up so your lawyer can reply to the court on your behalf.
My firm handles Whatcom traffic tickets all the time. Feel free to give my office a call.