Hi David,
Welcome to the forum. I hope your surgery goes OK. It's certainly good to have a project to occupy your recovery period.
I'm not an expert at sailing ship models but there appear to be two versions of San Felipe.
The 1:75 scale one is by Mantua Models and pretty expensive at around £750. it is also recommended for expert builders so you might find it a bit of a handful. Modellers might take a year or two on something this complex. It's not just the woodwork – there are a lot of knots!
The other is the one from Occre at 1:60 scale which looks rather simpler and costs a third of the price. This might be the better option.
**LINK**
As to how long it would take – well, that's anybody's guess as everyone builds at a different rate depending on the time available, their enthusiasm and their level of expertise. In that sense the Occre model would be the more practical match for your proposed timetable.
As far as disposal is concerned, model boats do not usually attract high prices, especially kits. You could be lucky to get the original kit price but it just depends on whether there is likely buyer. Also you would need to think about collection if selling on EBay as attempting to send a finished model of this type by post or courier is inviting trouble! Local auction houses might take the model but they will also take a high commission and whether there is a buyer on the day is a lottery I'm afraid.
Others may also have some comments.
Colin