Gil, yes, pvc is the way to go, but as you've found the drain tile to be beside the footing, rather than on top, by all means, hook your drain directly into it rather than reducing to the 2" pvc.
I do think I would make a test first; determine where your drain will connect into the tile, and cut the hole. (You'll want the drain to connect either directly on top, or in the upper half of the tile.) Then run water from a garden hose into the tile for a while. Watch to be certain the tile does drain freely into the sump; if your hole fills up over the tile before it drains to the sump, your drain tile in this area may have been displaced during the original backfill. (The rest of the drain tile IS on top of the footing, and it's "sagging" in that area because it's off of the footing.) You definitely want to be sure that the drain tile is working well, or your landing drain will be of no use.
As to the drain itself, yes, the reason for the trap is to stop airflow in the drain tile, since it's wide open at the sump well inside the home.
You mention you've reserved a diamond chain saw to cut your wall; have you ever cut out a basement wall section before? If not, did you check with a local concrete cutting company about doing this for you? If you're a novice to doing this part of the job, I assure you having this done for you is well worth it, and actually very reasonably priced. (I'm a general contractor, and we sold our larger concrete cutting equipment because we can have it done for us by pro's in that field better & cheaper than we can do it ourselves.) A concrete cutting service will use a hydraulic diamond blade wet track saw (rides on a track bolted to the wall), and will give you a very nice, square clean cut opening in as little as 1 hour. They will also (the co. I use does this at no extra cost; it's a part of the job) knock out the block, and break it up for you. They'll do most all the nasty work, including providing their water vacuum to clean up as the cutting is being done. We still own our diamond blade chain saw, but running it on a wall for long periods may give you problems; get's pretty heavy holding up high, most will not cut 8" in one pass, so you'd have to cut from inside & out, which will mean noxious smoke & fumes inside the home, difficulty aligning cuts inside & out, and it's an extremely dusty cutting method. (Just passing all this along in case you're not familiar with the process.)
Post back if you would, Gil, as to your feelings on this, and I'll add more details for you as needed.