On some pedals you can use an ordinary 15mm open end wrench to remove it but if there's not enough room to get a wrench in you'll need a pedal wrench. You can also use a hex key to install (many better quality) pedals but if they've be ridden a lot it's hard to get enough torque to remove them.

Any grease will do, I usually use marine grease from an auto parts store but given what you have, I'd go with the lithium.