Hyundai "SmartStream" Engines Compatibility

In 2018, Hyundai/Kia decided that the separate Gamma (small four cylinder 1.4, 1.6), Nu (medium four cylinder 1.8), Theta (big four cylinder 2.0, 2.4, 2.5), Lambda (V6s 3.0, 3.3, 3.5, 3.8L) and the tiny Kappa engines are all secretly one "engine family" called Smartstream. 

I'm particularly interested in the Theta/Smartstream 2.5 because I have an MPI Theta I in my car. According to stuff I found on the Korean language part of the internet, the Theta I, II and "Smartstream" 2.5L are all engine code GK4(something). This and internet picture comparison makes me think the shortblock is basically shared between the Theta I, II and Smartstream 2.5. 

If anyone here knows, I'd be interested to find out if the heads do bolt on interchange between Theta I, Theta II and Smartstream 2.5 short blocks. 

I'd also like to know if the 2.0, 2.4 and 2.5L versions share the same deck height or, if not, how much they differ. 

Lastly, I wonder if anyone can recommend a company that makes pistons for odd ball applications like this. If the interchange lines up reasonably well, I think I'd like to put a 2.5L SmartStream short block under a Theta I head. If I do this I'll need to get rid of the (so far very failure prone) stock GDI pistons in the 2.5L in favor of a stronger, lower compression piston to play nicely with my MPI fuel system. 

Thanks in advance, 
Ben

In reply to DaewooOfDeath :

I don't know for sure... but with the Theta 2.4L having a bore/stroke of 88mm/97mm and the 2.0L having 86mm/86mm... while the SmartStream 2.5 is 85.5mm/101.5mm... I feel like that might be a new block design.

supposedly the common thing the Optima Turbo people are doing is putting the 2.4 crank in with the 86mm pistons to get 2.2L.  Dunno how much of an option that is for you?

In reply to sleepyhead the buffalo :

It could be a new block, though I hope that the 2.5 has a smaller bore for the sake of thicker cylinder walls.

If not then a 2.4 or potentially 2.5 crank in a theta I might be the way to go.