To be in non pay status you have to be not be in pay status for the entire pay period, but all that means is some benefits don’t get stopped. Eg: you can’t contribute to tsp if you make no pay (non pay status), but that just means you and the govt only contribute based on what you actually were paid. Except for pay/non-pay status, all non-pay hours are aggregate for the year.
leave is different; lwop accumulates on a revolving 80 hr basis for the leave year, regardless of when it’s taken. Every time 80 hrs is accumulated, no leave is earned for that pay period. 79 hrs lwop / year = no leave lost.
for retirement/ scd time, as long as you work 6 months a year, there is no loss of time, like losing a year of creditable service for retirement.
life insurance continues for 12 months of non pay status without extra cost. Must of 4 consecutive months of pay status to reset that timer. Health insurance is the same, except you owe the premium.