Will Intruder 3 have a bigger budget than Intruder 2, or about the same? And was Intruder 3 planned way before the previous event was in production, or afterwards?

It will actually have a smaller budget, since we are splitting the budget for TIEs with Intruder 3 and our Oshii micro-series. It'll still be about 15 minutes long though. And yes, we started developing it about a month or two after Intruder 2 finished!