The name on your pilot and medical certificate should be your full legal name. Both the pilot and medical certificate should match. Yep, I've had a few issues. The FAA will send the paperwork back and delay you getting you new pilot certificate. If you have any questions please call your DPE before the check ride or the FSDO. BTW, Pilot Examiners can NOT change names on pilot certificates, only the FAA can do that. That means a trip to the FSDO.
Runway incursions, a big topic according to the FAA and it should be. I've posted tips & techniques on helping prevent incursions before but here are a couple of big ones:
Unsure of where you're at or how to get to where you want to go? Ask for a PROGRESSIVE TAXI. The controller will guide you step by step.
If you come upon Runway Hold Short markings and you don't have a clearance to cross or you're not sure if you have a clearance to cross, STOP!
I've been lost on an airport before, it's not fun. I've even cross a runway without a clearance (got a good ass chewing too). The common factor in both of those problems was I was distracted. I wasn't paying good enough attention to what I was doing and I screwed up.