Well, finally got all the Push Lock fittings installed. Soaked the hose ends in boiling water for 5 minutes and used dishwashing liquid on the fitting barbs and a little in the hose end. Still took some mighty pushing and a little "fixture" to help steady the 90 degree elbows. Makes for a real clean fire sleeve installation. Somewhat intrigued by the freezer approach, but I was in get it done mode rather than experimenting.
Turns out that I will have to remove the oil cooler to install the fittings into it anyway as the 45 degree fittings will not clear the engine mount to turn them (at least in my installation, your results may vary).