Do we have to use a current card art? That would make it ridiculously easier, as there is software that changes the picture to that style nowadays.
I think at least making is do something new should be mandatory.
You have to create something completely original...
Any size restriction for Artist?
The final submission ought to include the new art
within the card; in other words, you have you use the CI&A card image editor to import your pic and write down the card's text and stats (thus recreating the card). Since it will be imported, it will be resized by default (however, you can include the original art in a spoiler or something).
Can we do holy cow for the writing task?
It is technically in-game, so yeah.