Planning for migrating thru a 3rd party tool from SharePoint 2010 to 2013 migration

We have to migrate a SP 2010 web application to SP 2013. Total 34 site collection under 1 web application. Data is only 46 gb. We have to use a famous 3^rd party tool which generally does a good job for site collection migration.

Now we need few suggestions from real-time experience guy who has done migration through Quest tool.

Basically we want to use famous 3rd party tool only for site collection upgrade, all previous steps we have plan to do manually.

Our planned steps are:

1. Prepare (This step is not by the 3^rd party tool)
   1. Gather information and clean up 2010 farm – Not by 3rd party tool
   2. Prepare 2013 farm
      1. Install software
      2. Configure service application
      3. Configure farm settings
2. Upgrade databases (This step is not by the 3rd party tool tool)
   1. Copy databases
   2. Upgrade service application databases
   3. Create web applications and apply customizations
   4. Upgrade content databases
3. Upgrade sites (site collection)
   1. Begining from this step 3rd party tool tool needs to be involved.

Note: we have some doubt that if all service applications data can be migrated and reusable or not?

If not reusable then, we have to build particular service application from scratch?

We need your help on the following questions:

1. Is our planning correct that we can do steps 1 & 2 without any third party tool?
2. Only in case of site collection upgrade we can use the 3rd party tool.
3. In this case can we migrate all user privilege through the 3rd party tool while migrating site collections?

Please help with you real-time experience if our plan is realistic.