Mario's recovery distance is pretty irrelevant while he's edgeguarding since most of his edgeguarding options don't require him to move far offstage and he still has the cape glide if he needs to go far offstage quickly. Also, cape and FLUDD both ignore SA frames and Charizard's glide and jumps are both pretty slow
Cape doesn't turn anything around during SA frames. They take the hit and the damage, but remain going in their original direction. That's why you can't cape Lucario during upB startup or Olimar during his downB. Fludd works fine though IIRC.
It doesn't really make much difference though. That just means that Mario has to pressure him into using it before he should or cape him before/after the upB.
I have Charizard as 60:40 and Ivy as 55:45
Charizard because I'm not seeing how he keeps Mario out. Rocksmash is a great defensive option normally, but I've found that cape can cause it to seriously backfire. Flamethrower's pretty decent as well, but it has punishable lag if you miss. The best weapon to have against Mario is a means to keep him from getting inside your range. Something like Ike's/ZSS' jab, Marth's Fair and DB, or Snake's tilts that keep him from consistently getting close. If Charizard has a means to do this throughout the fight, then I'll concede to even or adv Charizard, because he has the KO power, range, and general priority IIRC.
Ivy's a 55:45 imo because he can definitely keep Mario out well enough, but his defensive game has holes in it. Mario's MUCH faster than him, so he can take advantage of them and get inside, especially with fireballs for approach. Punishment won't be heavy if bullet seed and Nair are truly combo breakers, but Mario also kills him pretty quickly from Fsmash because of that silly fire mechanic, and gimps him pretty easily. Ivy kills well and outranges Mario, but Mario will be killing just as well, and even has the option to camp him.
Edit: Mario's offstage defenses are cape for stalling/dealing with oncoming projectiles or attacks, fireballs for preventing offstage approaches and ledgehogs (including tethers), Fludd to push lighter opponents back onstage for a safe upB to the ledge, Bairs if you decide to turn around with cape, Fair meteor if you aren't massively disjointed (ZSS, Mario, or Shiek for example). The greatest defense, however, is Mario's upB with invinicibility frames on startup, high priority, and stagespikes at 0% if you're on the ledge.