Having assembled the Prusa i3 MK2s, I'm happy to suggest the MK3 with no reservations. It's clear to me from the review videos that the MK3 will be easier to assemble, should you choose the kit version. I recommend that you purchase the kit version, as it gives you a bit of education as well as saving a few dollars. The kit is shipped with everything necessary to assemble it and the instructions are superb.

The calibration process has been improved from the MK2 to the MK3. It was the proverbial piece of cake originally, now it's that much better. The structure is more rigid and less prone to minor assembly errors. Having read the assembly instructions, I can say that if you can't put this kit together, you might not want to own a 3D printer.

A starter instruction booklet was shipped with the MK2 and I expect the same for the MK3. It covers all aspects of tuning (minor stuff) as well as good 3D printing practices.

The fit for parts printed on the MK2 was excellent. Since the MK3 is likely to provide improved accuracy in that respect, expect excellent results as well.

Rigidity in a printer is important for quality printing. I have no experience or exposure with the Creality printer, but I think it's going to be difficult to find a printer with less flex than the genuine Prusa models.

You asked about smaller nozzles. Small nozzles will require the aforementioned rigidity, plus precise motion control of the print nozzle assembly. You're likely to get that with the Prusa.

With respect to the large print you require. Consider that you could angle the model from flat on the bed to 45° to enable it to fit in the build volume. If not, printing in pieces is a practical answer. The adhesion question can only be answered by the glue you select. Long cure epoxy will have greater strength than quick cure epoxy. Some superglue types may work, but they tend to be brittle over time. Any flex on a long part may cause separation. If you're printing in ABS (needs enclosure) you can acetone-weld the parts and get even stronger results.

I had great fun assembling the Prusa i3 MK2s for the local public library and think you might find your money well spent.