On another note, I think I may have asked before but forgotten the answer (or didn't receive one) but what would you consider the upper limit of the size of an object my character could absorb? Where is the upper limit at? Suit of armor -> Table -> Cupboard -> Piano -> Large Boulder -> Hut -> House -> Mansion.
If it really comes down to
'can I pick up the dead hydra and place it in my inventory?' I'll use the D&D rules for the bag of holding, with your primary stat determining your max limits.
Stat Lv. 6 [or whatever level you have it via feat] (weight limit) 250 lb (Space limit) 30 cu. ft (The size of a refrigerator)
Stat Lv. 7 (weight limit) 500 lb. (Space limit) 70 cu. ft.
Stat Lv. 8 (weight limit ) 1,000 lb. (Space limit) 150 cu. ft.
Stat Lv. 10 (weight limit) 1,500 lb. (Space limit) 250 cu. ft.
Just scale up. It'll be broken no matter what I use, so might as well go with established rules.
Also, there's eventually going to be a question of where all that stuff is actually going...
Also, if she (or her equipment) is in touch with a large number of smaller objects (like the chunks and blood of monkeywasp from the enemy Anders blew up) does each chunk have to be painstakingly and individually sucked up, or can she quickly clean herself by drawing in all the giblets, then pushing them out again in a neat pile? The imagery is a bit disturbing, but this is one of the weirder abilities to figure out its limits and how it functions.
Yeah, let's just say if it has no mechanic effect, you can do it. Like, cleaning yourself off, no problem.
Making a portable air-bubble by sucking the water out around you underwater, so you can walk across the ocean floor? I dunno!
..
As for all the other questions, I think taking disadvantage on your D20 as well, is a logical choice. I'll add it to the house rules.
Also if anyone starts AOE'ing the whole map at once, there's going to be some friendly fire tho...haha. Ranged AOE in general should be considered dangerous if you fail the roll.
In fact, I think when I'm considering effects related to failed rolls, those rolls done with an advantage will be generally slight negative in return for success/allow you to take back your action (You can land safely jumping on the Hydra's back, but you'll be prone, or do you abandon your jump and try again on the return swing?), but those done with a disadvantage will be a choice between two 'evils', as in you're going to succeed, but you probably don't want to.
(You lost your grip and you're falling. Do you aim for the Hydras gullet, trying to balance between his teeth, or try and land aside the razor sharp poison spines on his head?)