Didn't realize this was a retrospective at first. Will still comment as if it isn't. Not much use to you but hopefully useful to others reading along.
ENGINE:
The crossflow and the wedge take virtually the same gasket set, same bearings, timing chain, oil pumps, etc. Mecaparts is a good source for those few different parts. Lots of wedge distributors out there. It's the crossflow ones that are hard to come by.
Yes, Renault engines are very simple EXCEPT for setting liner protrusion, aligning the head on assembly, and retorquing the head at the specified intervals.
Liner protrusion is an absolutely critical step to achieve a proper cylinder head gasket seal. Follow the manual carefully and invest in a good dial gauge (or the factory tool if you can find one, Peugeot have a similar tool that works as well).
Second, there is a only a single dowel on the head so that you can twist it if you have to remove the head in service. You can't lift the head as it may lift the liners and tear the paper base seals. This means you have to use a removable guide to align the head (Steve Veris can supply the tools). The head needs to be properly aligned or the distributor gears may destroy themselves.
Finally you need to retorque the cylinder head (and adjust the valves) after initial start-up and again at 1000 miles/1600 kilometres. High performance crossflows also require retorquing every 20K kilometres.
So many Europas are found headless because no one reads the manual before tearing into them. The head is ripped off for a quick gasket change and then the problems really start. Properly maintained these are very tough, long-lived and delightful-to-drive engines.
BODY:
I'm not a body chap/ette but I have found out the hard way that early Lotus fibreglass is quite different from other fibreglass vehicles and boats out there. It is poorly and thinly laid up. This means it is very prone to gel coat cracking. Unless properly repaired, these cracks will reappear, period. Miracle fillers and primers will not do the job. My body work came back absolutely, unbelievably gorgeous. I'd never seen anything like it in my thirty years of car repair and restoration. A few months in, the first cracks started to appear under the paint. Now, it is simply covered with barely visible cracking under the paint and clear-coat.
Again, this is not my area of expertise but it was of the place I hired and they got it wrong. In my opinion, the only way to stop the cracking is sand all the paint and fillers off, veil-coat the entire body and then build up from there. YMMV.