I have many issues with my house where should I start?

Vermiculite can often be contaminated with Asbestos, so I assume that is the testing that you did, and great if it came out pure. If you have determined that there is no safety risk in keeping the Vermiculite in your attic and you plan to insulate over top of it, be sure that it is properly vented at the soffits and with a roof peak vent. You could use Rockwool batts, I don’t believe they still provide a loose fill insulation. Alternatively you could use loose blown cellulose insulation. 

As for  your question about sealing it, that is a very wise idea. You could have a blower test performed to see how leaky the house is, that can also help you pinpoint any breaches in your air barrier so you can find and fix them. 

That list of questions is pretty long, and I think the best place for you to start is figuring out what your budget is to make repairs, as that is a rather extensive list. 
The best way we can help at this point is to lead you to some relevant pages that cover the topics you are talking about. There is a search box at the top of our home page where you can enter tag words, but here is a list of a few that seem like they may be of value to you as a starting place. These will help give you a working knowledge of what is important in a home and how to best proceed with home renovations and energy efficient upgrades.

Please have a read on a few of these pages, and once you have a better idea of what you want to get done and your budget we are more than happy to help, please write back, and separate any questions in different threads so we can tackle them one at at time. 

• Tips for a successful build or renovation project

• How to stay on budget with renovations

• How to insulate a crawlspace

• How to remove radon gas from basements and crawlspaces  

• How to insulate a CMU cinder block foundation

• The best way to insulate a basement to avoid mold

• How to insulate an attic and avoid ice daming

• How to install siding so it can dry

• Choosing the best exterior cladding