#1
I play a lot of emo, alt rock, post-hardcore(not really heavy), grunge and things like that. I love Fender Jaguars. Do you think the Fender Jaguar HH can give me a heavy enough sound for that? Also is it a very versatile guitar. I've only gotten to play one once so I don't really know

and yes I will go play another before I buy one
#2
We need more information mate
We need:
1. Budget?
2. Location?
3. Home or gigging guitarist?
4. Preferences for your guitar? (ie do you want a whammy bar?)
5. Are you going to buy new/used or both?
6. Current amp
]
#4
all that stuff you posted isn't really heavy music to begin with, but yes a jag will do what you want. In fact, I feel like the HH was made specifically for those genres.