Speaker repair...is it easy?

If the air gap has ferrofluid in it, the fluid will help to keep the voice coil centered.  If you need to replace the ferrofluid, please, for all that is holy in this world, use audio grade fluid.  A reputable speaker repair service will know and understand how to use ff in a driver.  Ask what type of fluid they use.  If they say EFH1 or something they got off Amazon, DO NOT POWER UP THE DRIVER AND DEMAND YOUR MONEY BACK.  This is not audio grade fluid and will ruin your drivers.  I have no experience with Dunlavey speakers, but I would suggest Ferrotec APG L11 as a good substitute for what was in there.  Good luck with your repairs!
- Vanessa

Wonderful! A Vanessa that specializes in ferrofluid. Welcome:-)

I’ve used Bill at MillerSound.  He’s fantastic!!  And a great guy. 

I've done many speakers from 4" to 12".
There are kits available from Just Speakers or Orange County Speaker Works online, just to name a couple.
Its very important to keep the cone centered around the voice coil, or it will rub if  the surround is glued crooked. Some kits include different thickness shims, in order to keep things centered.  That requires cutting away the dust cap, centering the cone with shims, gluing the new surround, and replacing and gluing the ,(usually provided), new dustcap that came with the kit. Use isopropyl  alcohol and q-tips to clean the old glue from the frame.
Just Speakers,(not affiliated with them), provides full instructions.

I never try to do this, because of the voice coil gap tolerance. I leave it to the pros. 

Gabriel Sound in NJ does my Altec 604Cs. Price is reasonable.