I don't see any hate here, just objective recommendations from people with experience at these places.
Why did you come onto this website, for advice or for conformation and praise for your brilliantly thought out itinerary?
Yes it is doable in the best case scenario, but hardly advisable.
You seem fixated on flying into Frankfurt and training immediately to Munich. Why? There are lots of flights from DFW to MUC and flying open-jaw (DFW to MUC, FRA to DFW) is probably not much more than RT DFW to FRA. Full fare FRA to Munich will cost you over $100/person and take almost 4 hours. There are less expensive SparPreis tickets for that route, but they are non-refundable, valid only on the booked train - not advisable for a flight arrival that could be delayed.
You MUST reserve a tour for Neuschwanstein. You're going to be there at Oktoberfest. I went through Hohenschwangau during Oktoberfest a few years ago, and the line at the ticket kiosk was enormous - more people standing outside the kiosk than inside. I think by noon, all tours for the day had been booked. You must book a tour as close as possible to the start of castle tours at 9 AM. Since the website says you MUST pick up you ticket one hour before your tour start time (or lose it), you should be at the kiosk when it opens at 8 AM, which means leaving Munich before 6 AM and preying there are no traffic delays.
The walk up to Neuschwanstein will take about ½ hr if you are fit, but that time is included in the one hour advance for ticket pickup. The tour takes about 40 minutes and the walk down is about 20 minutes, so you should be able to return to Hohenschwangau and your car about an hour after your entrance time.
I don't know how long it takes to do the paragliding. Do you need reservations? But after the paragliding, you still have the 2½+ drive to Rothenburg.
So, with Neuschwanstein reservations, that day is doable, not without.
You are planning a drive of about 100 miles to the airport for a flight home. What could go wrong with that, and what would be the consequences if you were delayed. I'd drive from Cochem to Mainz the evening before and return the car, then stay at one of the three hotels (Schottenhof, Koenigshof, or Hammer) right across the Bahnhofsplatz from the Mainz Hbf and a short S-Bahn ride to the airport in the morning. Or, return the car in Cochem and take the train from there to the airport in the morning.
BTW, it hardly matters, but Ernst is UP, as the river flows, from Cochem.