Well, you could have a Shard-arrow, but you would need to use one of those shardbows like they used in the chasmfiend hunt. You wouldn't ever run out of arrows, either because you can just summon the arrow back when it's done.
You wouldn't Instantly die after stopping compounding because you're already perfectly healthy when you stop; Feruchemical gold health doesn't go away after you stop tapping it.
You would, of course, have to deal with no longer having Wolverine-level regeneration.
I don't think that the human-ness of the spikes makes a difference with the height gained; Koloss just keep growing till their hearts fail. A Trolloss would have a much higher limit, like 30-40 feet as stated before.
Sell. I still don't think she'd be comfortable taking that many people's Breaths.
Since it got missed, I'll say it again.
We will see a Returned Sentient Awakened Object. (something like Nightblood, but Returned instead of man-made.)
You know, for April Fool's next year we should all pick someone's image (without their knowledge) for our profiles.
That would be confusing. (if this has been done before I apologize)