Those three items are generally required to interview at any airline, and will most certainly be required before you get a class date.

Even if you don't need one for your current job, a current 1C medical is always required to apply. That means you can't let it lapse to 2C, so you'll need to renew it every six months until you get hired...then you can let it lapse to 2C privileges and renew it annually (until you upgrade).