I discuss this in-depth here: Q Module Pack #22: ESSENCE 2 - #53 by SaintSovereign
With the first, no – it’s not redundant. It’ll most certainly work well with Emperor and any title that doesn’t have some form of anti-recon.
With the second question, if you include something like Wanted: Dream Boy Core, you wouldn’t need to include anti-recon. The anti-recon scripting in those titles will latch on to the entire custom. However, if you REALLY wanted to work on recon management, including the Experimental Anti-Recon Module in a custom with a core that already has the scripting will boost its effectiveness.
Remember, the Experimental Anti-Recon Module was built SPECIFICALLY for customs. The version within a core is geared toward that title, but to make it easier for everyone, it can also work with the entire stack (including the custom).