Is that the Wesley that shows up in Buffy Season 3 as Giles’s replacement?
Yesley. Biiiiig changes.
Yes. If you haven’t seen Angel, you should check it out – if you enjoy Buffy, it’s unlikely that you’ll be disappointed with Angel. Angel season 1 aired back-to-back with Buffy season 4 starting in late 1999, so I recommend you watch the two shows together (e.g., 4.1 of Buffy, followed by 1.1 of Angel, 4.2 of Buffy, 1.2 of Angel, and so on). There’s a lot of neat little crossovers that you may not pick up otherwise.
Plus, if you like Cordelia and Wesley Windam-Pryce, they become regulars on Angel, and their characters become much more interesting and complex as the show progresses. So I’m told… 