Rental unit AC leak, added freon for 3 years. R22 freon在张家，是换新的还

This is a remote rental unit.  Tenants said AC is not working again, I know it is time to add Freon. 
The realtor who I work with find an AC guy, his friend.   This guy's suggestion is to put a goodman AC (outside unit) for $1850, with no permit; add $700 extra for permit.   After some research, I found out that the unit he is adding is the R22 unit, not changing the coil.   He said this unit does not use R22 Freon, is that true? I cant find such infomration on this.  If it is R22, it has to use R22 Freon. 

If change the coil (that is with the R410 unit), it will be $3550.  He also mentioned that add $1000, I can change the heater too, because the labor of changing coil and heater is the same. 

There is too much technical details beyond my understanding, also I see online people say goodman is not a good brand.   Can the expert here give me some suggestion or guidance.  There are too much involved, I dont know what is the right action. 

I probably sell the house in about 4-5 years.  

Thank you.