The first one is guaranteed. You can't spot dodge the fsmash. As for the second one, you can avoid the fsmash all together with some di. So the first one is what Marths should be using. And one more thing, you can't nair between the fthrows. =/
oh sorry for not making it clear kaylo
and the first 1 isnt guaranteed. everytime marth dthrows you, you have to have accurate timing but you WILL spot dodge the fsmash coming.
the second 1 if you notice try air dodging, you'll see pika go into the air dodging position but you can still be re-grabbed, so i though why don't i try and use his fastest move.
when Ixis messed up the chaingrab pikachu knocked back marth with nair, when he done it right i gave marth the damage of nair but grab armour got me re-grabbed. if it doesnt work for you your simply not timing it right. if it helps spam that A button like crazy and you WILL notice i'm not wrong here.
and 1 more thing, after the 3rd f-throw, you are garrentied to get fsmashed (maybe not tipped), but if marth tries a 4th f-throw, that when you can get away unpunished by a fsmash
clearly there are doubts so i'm gonna try and meet up with Ixis in the next 2 or 3 days to record and upload some footage proving it kay.
[Edit]: oh and please mind my sentence structures, i'm dyslexic so i struggle to form sentences properly, but im working on it!