Can an employer only pay me 50.8 weeks, put 5 days in arrears as a salaried employee?

So I have a question about exempt salaried employees. My employer is changing payroll from a bi monthly payroll to a biweekly payroll. They plan to implement this on Jan1. In 2019, they are going to pay us the first 4 days of the year, hold the next 5 in arrears, and pay us our regular salary the rest of the year. That only leaves us with 50.8 weeks paid in 2019 and 51.8 weeks pay provided. They aren't paying us our full salary for the year. Is this legal according to federal law?

Second thing I have an issue with is that we are currently being paid bimonthly for 2080 hours a year and some years there are 2088 hours that we are required to work and 2096 depending on the number of days. Is it legal for them not to pay us for those days?