Interesting read. The photos are great. Thanks.
My tubes were very, very stuck. I used an old non-OEM pump to try out a method for removing them prior to doing the "real" pump.
Find a bolt or other solid steel shaft that fits very tightly inside the tube, but don't insert it yet. Heat up the housing. I had to resort to an Oxy-Acy torch to heat the housing as my tubes would not come out under normal propane torch heat.
Insert the bolt or shaft and then grab the tube and twist it out. The insert prevents the tube from collapsing.
Too much heat could damage the seal/brg so do this on an empty housing or before the rebuild.