There's about .7kPa of atmos on mars. I'd have a hard time seeing how that would meaningfully influence escape or entrance velocity. In fact it should make entry easier because you'll have a higher resistance coming in meaning you'll have to do a lower deceleration burn.

Could you provide a source, of someone with experiance in this sort of work, telling me why this is the case? Why does this completely change the game? Why is a moon landing not the eaisiest "we know basically what we're doing"?