Best practice for an Employee on-boarding process

Hi - new to Smartsheet and my MD and HR Director have asked me to look at rationalising some Google Sheets they use at the moment to track employees from initial interest through to starting with the company. 

I've looked at a couple of templates and started down the road of creating a sheet which has Surname as the Primary Column and then froze the next column (First Name) together with Surname to make it easy to keep the name in view when filling in the rest of the Columns. 

As part of the process, another department needs to run through a checklist so I created a separate sheet which links the Surname, Forename and Status columns in but then provides a series of other columns to be completed, to avoid the first (I call the "Master" sheet) from being 45+ columns. 

I then discovered the 500 row limit on linking which could potentially be a problem and then also looked at another template where each new employee is a Parent Row and then all the tasks associated with onboarding are child rows, with columns where checkboxes can be set, or data filled in. My problem with this approach is that a lot of the columns will only relate to one child row, so it seems ugly and also, the sheet could become very large very quickly

I was wondering if anyone had come up with a neat solution to onboarding with similar requirements to those I've outlined and if you'd be willing to share this with me