A team of 5 level 60 champions with mostly 4* gear could certainly finish dragon up to stage 20 if that's your question. Though yes, it may take weeks or months to get from dragon 13 to 20, as you may need to build new champions, upgrade your gear, and so on. 

Seriously? If you can clear 16, you should be doing vladmeir strait on hardest difficulty you can boss battle right now.

That is ... just terrible advice.

For starters, campaign is only meant for farming exp. You should never be farming campaign for gear.

Secondly, you should never be farming campaign bosses. They give a lower amount of exp per energy, they cost more energy, and they are generally less reliable on auto due to Mortu's hidden skill Peril.

That  was  my  question  mostly.    Does  gear  need  to  be  5*.    Didnt  ask  it  well.

Following  up,  if  20  dragon  is  the  goal  should  i  be  upgrading  4*  pieces  to  16  or  is  that  a  waste?

Good 4* pieces are worth 16 - yes, they'll get replaced in a few months' time probably, but in the meantime you still need them to do their job. Don't obsess too much over the number of stars - there are some people who start discarding all their 4* gear pieces as soon as they have regular access to 5* ones, that's just stupid, you should always use the best gear you have available, which for a long time will include certain 4* pieces with great rolls. 

I would almost never upgrade a 4* item to level 16. You'd really have to justify the specific use case.

Generally, I wouldn't even upgrade 5* to level 16, although from your current progression point it may be selectively necessary. Just make sure you choose the proper gear to upgrade - for example, you should pretty much never upgrade a weapon to level 16 on a DEF-based champ, and similarly, you should rarely upgrade a helm/shield to level 16 on an ATK-based champ, simply because they don't really benefit that much from the primary stat increase, and 5* items are ultimately replaceable.

Good candidates for upgrading 5* gear to level 16 are:

Speed boots

ATK/DEF/HP % chest

Crit % / Crit damage gloves

Also, to a limited extent, ATK/DEF/HP % boots and gloves can be useful, although you need to be careful about those, since you're setting your champs up to require specific teams in order to have those work properly.

Gear you should almost always instantly sell are:

Flat ATK/DEF/HP gloves/chest/boots

Also, for your current progression point, you should probably avoid ACC/Resist chest - they're selectively useful, but you shouldn't need them at the moment. 

You  can  farm  campaign  for  gear,  but  I  would  only  recomend  it  on  Brutal  while  farming  food  at  the  same  time.  Also  the  only  pieces  I  would  farm  are  Speed  amd  Lifesteal.

Also,  do  not  sell  Accuracy  chests.  They  are  particularly  useful  in  early  game  to  get  higher  Accuracy.