ok I was a bit confused there. The Epihones were built to last 

ok I was a bit confused there. The Epihones were built to last 

Looks like a bad crack on the ribs under the neck joint. Factory made guitars can be a nightmare to take apart due to the type of glue used. The wood often splinters. I would try and inject some wood  glue in the crack and clamp from inside the sound hole using a block of wood as a spacer.

Does the top block looks sound or does it have any cracks.

I’m not familiar with Maccaferri is it a type of jazz guitar. I did notice the scale on your fret slotting template. I do have a high end Gypsy guitar with a zero fret made by Polark in Israel which I bought before I found Bailey Guitars and wish I had waited a bit longer as I would have preferred to buy in U.K. 

One advantage I do find is that having the nut further away it doesn’t catch the hand while playing a barre F shape as I have big hands. A build for the future I think once I have finished a few violin bows that I’m working on.

Zero frets tend to be used on cheaper model factory production instruments

How very dare you Rocknroller!

But I will forgive the generalisation given that you mention gypsy jazz guitars. All Maccaferri guitars, even the nylon stringed versions, were produced with a zero fret, the thinking being that this sets the exact contact point with the strings more accurately than relying on the filing of the slots in a nut, which if angled incorrectly, can result in the contact point being further from the bridge than it should be or just generally imprecise.

You are correct that it is often the case that a slightly higher profile fret wire be used for the zero fret but I didn't do this on my builds and it hasn't caused me a problem. The zero fret does mean that the last little bit of fretboard can be pretty fragile and I would recommend filing some of the 'set' off the zero fret tang to relieve the stress on the fretboard when tapping/glueing it in. 

The scale length runs from the centre of the zero fret and my fret slotting templates (which have the two Maccaferri scales) make allowance for this by adjusting the zero fret slot position by half the thickness of a fret slot. It's not a lot, only about 0.25mm, but it's worth doing just to remove an unnecessary error. In actual fact it is all of the other 'nut' scale lengths which are adjusted for the first fret position (by + 0.25mm) but as we are talking about zero fret set ups I hope you get the gist.

Darren