The real problem is the fleet.
Condor have a fleet of 20+ year old A320, B757-300 and B767-300 which will need replacing soon.
Thomas Cook UK and Scandinavia have a slightly more modern fleet of 15 year old A320 and A330, and younger A321ceo.
Any new owner will be investing in an airline group where significant capital costs of fleet replacement will be required in the fairly near future.
Lufthansa may be interested in purchasing Condor and running it alongside Eurowings with a more modern A320/A330 fleet mix. But the existing Condor fleet will not bring any efficiencies. Apart from a few airport slots at FRA and MUC, there seems little benefit from what could be achieved by simply internally growing Eurowings.
Virgin may be interested in some of the A330 long-haul leisure routes, but the short-haul fleet is less appealing. The market is now dominated by easyJet and Ryanair who have their own order books of next generation Neo and Max aircraft, so little need for a non-standard A321ceo fleet. Again there is a slot holding at LGW and MAN, but nothing worth the big price tag of buying a whole airline.
So the other alternative is an investment group such as Indigo Partners. These companies are purely looking for a short term return on investment. I'm not sure they would see value in purchasing an aged fleet requiring a large future investment in fleet renewal. Particularly, when they will have no reliable income stream once the tour operator is divested from the airline.