There are a bunch of set ups. This video may contain the answers you're looking for.
I assume it's in the above video, but if you're just running straight at the person and you already have the metal blade in hand as an item, you can short hop throw it from short range into a confirmed up tilt. I believe it's percentage dependent.
For more set-ups and documentation on the percentages for each, you should check out the resources on the Mega Man Discord.
Not at all, we are all quite active there. I'd even say it's the most active Smash Mega Man community atm and the best place to learn and improve. In fact I moderate the discord server. Here's the invite link: https://discord.com/invite/fBfHuKS