There are a number of random encounters involving Peacekeepers, one of which is outside of ToA. There are others at various locations in Nebo Terrace, North Kryta Province, Watchtower Coast, and Scoundrel's Rise. Most of them can happen more than once, including the one at ToA, while others will happen only once per character. Usually the Peacekeepers involved will turn hostile after some dialog, though there is one case where they simply talk to the farmer and then walk away without becoming hostile.
Spawns have changed in most explorable areas of Kryta. Most of the undead are gone, replaced by Peacekeeper and White Mantle groups, plus a few odd spawns such as the lynxes you encountered. After all, it's been years since the Lich was defeated, so one would expect the undead problem to be largely cleared up by now.