Use conditional formatting to track expiry dates in multiple fields

Hi,

Am struggling to format this spreadsheet correctly! Am an administrator for a transport company and need to keep track of 100+ subcontractor insurances. There are 8 different kind of insurances/fields (some insurances apply to businesses operating from certain states, so some cells are blank). The expiry dates all vary, and every time i use the formulas i've googled it fills blank cells and overrides the formula i entered previously!

Need to come up with a way to format cells so:
Green = Insured from 3 weeks from now onwards;
Yellow = Insurance set to expire within 3 weeks (to send reminders to subbie to resubmit)
Red for all expired from today prior.

Load allocators need an easy and simple way to view so they can know which business can load for us and which can't.

Edit: As an industry that is 20 years behind the rest of us and highly resistant to change, using Outlook Calendar reminders or something similar will not be as effective. If i can send a copy of this at the start of each month they can use as reference, it would be much easier! Am currently using conditional formatting for 'values between' but this needs constant maintenance - and this spreadsheet needs to be up to date so all employees can look at any time, and assign a loadAttachment 257682.
Due to privacy restrictions, I have uploaded a modified version, omitting sensitive information e.g Business names, vehicle registrations, ABNs etc



Any help would be appreciated!!