Forget the Jetta, those are endless moneypits. Both the Mazda 3 and the Mazda 6 are excellent choices. A Ford Fusion is a good choice too as long as it doesn't have an EcoBoost engine.

Get the Mazda/s, out of those options. 

If buying used, be sure to have it inspected by a professional mechanic, before purchase.

All the best!

If the fusion was more in the early 2010s range, that wouldn't be a bad choice. But the newer mazda's are considerably better. 

Mazda has a relationship with Toyota now, and their quality has increased dramatically. 

Test drive the 6 and the 3, see which one you like better. 

Of those definitely go with the Mazda’s - pick the naturally aspirated engine versions over the turbocharged if you can.  Also, starting with 2018 model year for the Mazda6 to the present, the naturally aspirated 2.5L Skactiv-G engines came with cylinder deactivation.  I would avoid those, which means looking for pre-2018 model year with the 2.5L engine.  For the Mazda3 I don’t recall which year they offered cylinder deactivation, but check the Mazda3 brochure (I think by 2019/2020 they had it).  To add confusion, it came on certain trims (but just check the brochure for each year to dial it in).

Go with the Mazda