OK so this tree is new, only about a foot tall (I was told it was a 2 year old fig) and it had one figlet coming in already.

However since its potting it has dropped its one large leaf (yellowed and browned at edges) and almost a second.  The logical reason appears to be sunburn.  

SO, I put it more or less out of the sun, it currently gets only about a half hour of direct sunlight a day.   I purchased a moisture meter and the dirt has always been on the wet side, and still is.

Strangely however, I checked the plant this morning, and the figlet has suddenly deflated, and slightly browned.   But to add to the difficulty, the REOTEMP MM17 moisture meter I bought has claims in its Amazon reviews that it reads 'over wet' and needs 'calibration'.   Nice.  So I added more water, but of course it may be too much who knows, thanks to the meter.

So what gives?  I've been told figs need 8 hours of sunlight a day, this is getting 1/2 and browning.   Its got plenty of water but figs are shriveling.   I'm lost.......

Looks good to me. I'd say you are over thinking this figs condition. Continue as presently and give it time to root into it's new situation. Keep it mostly in shade for several more weeks while gradually increasing light. I think it will be OK.

The strange thing is the figlet is much smaller than it was yesterday, and it looks burnt ??!    Seeing as its the only fig currently on the tree, kinda hard to miss.

I didn't know they shrank....

OK the fig died, the plant dropped it.

I have a 7 month old panache about the same size as yours that the same thing happened to. Prolly best in the long run to get rid of the figs on a small tree.