I agree with aghadowey.
I don’t see the point of this. You might as well find a photo of a stranger on the internet of the approximate age and era and say it is your gg grandfather. You know it isn’t and it would be the same for any hybrid photo you could concoct.
May be a bit of fun, but nothing more.
My Heritage do animations, colourisation etc with photos, but I don’t think they do anything like what you are after.
You could try posting the photos on the photo restoration board to see if any of the clever people on there could work some magic.
Added: I have family members who look completely different - my daughters are the most recent generation - they have similar eye colour, but nothing else suggests they are even related let alone sisters. DNA tests prove we are all related though.
