Corny Kegs2

Just put my first all grain batch of a Domestic IPA in a 5 gallon Corny Keg and pressurized it to about 35psi for 2 days on my cold back porch. I had to remove the ball lock fitting (gas side) to install a pin lock fitting for another keg I was reconditioning. I checked the connections on the ball lock keg with water and there were no apparent co2 leaks. Am I correct in assuming the keg should hold pressure indefinitely? I have a total of 11 of these kegs and am trying to get all of them in shape. Any tips for long term storage? (full or empty) I have been using PBW to clean them and it seems to be doing a good job. Do the washers under the dip tube and short tube usually get replaced too? Is it ok to use a light coating of keg lube on ALL fittings and washers (poppets too)? I am new to kegging and any input would be appreciated.