Thanks for all of the help here and in a couple of other threads, and from Lulzbot tech support and I-T-W (where I got some of the parts). I got the replacement PEI installed with no problem (a tip from Lulzbot tech support: but the print bed in the freezer overnight, then peel off the next day).
I had my daughter and a couple of friends from her 5th grade class come over to help replace the print bed onto the machine and mount the replacement tool head. They did most of the installation themselves. About the only thing they couldn’t seem to get by themselves was getting the zip in place on the print bed connector. I checked the snugness of the various bolts. They found the e steps calibration process a bit boring, so took a sledding break while I did that.
The printer is up and running well. Of course the kids had to design and print a couple of things to test it out.
We’re still using up the first roll of PLA, then we’ll probably move on to the 3 rolls of HIPS we have. After that, we may try out some of the other recommendations folks here made. We will get at least one roll of ABS for printing replacement parts. All the kids in the classroom thought it was pretty cool that the printer could make its own spare parts.