You are right, just drill out the rivet using the same sized bit, being careful not to push the rivet or bit through the vinyl liner. Unless the holes are not fairly round still, I would not worry about a washer, this catch is not creating very much pull at all. I have done a bunch of rivets lately on the shell without washers, and being near 3/16" thick, I am not worried about pull out at all.
2017 Escape 5.0 TA
2015 Ford F150 Lariat 3.5L EcoBoost
2009 Escape 19 (previous)
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