You can top off the drive lube. That is filled from the outdrive and pumped up. Once it hits the resevoir you stop and it continues to slowly fill the resevoir. It takes a while to stop rising. If you pump until the lube reaches the FULL line, then when you stop it keeps rising and overflowing. I'm going to guess the service person, walked away and expected you to top off the remainder in the spring. That is typically how I do it as well.
The engine oil doesn't circulate in the dipstick tube. So if there is water in there, it wouldn't show up on the dip stick. You could suck out 1 -2 quarts and look at it rather than doing an entire oil change. You would run the engine first, then stop it and wait a few minutes, then pump out and look at the engine oil for the evidence of water.
If no water, top off the oil again until it is full.