“All elf/human babies are human.” Hah. Ahahahha. HAhahahahha.
Let me learn you a thing. (Long genetics post to follow, the following should also apply for elves/any race capable of producing offspring.)
The above statement refers to the fact that all elf/human (50/50) offspring appear to be human in appearance. This is called phenotype: a term used to describe the physical manifestation of genetic traits. Phenotypically, such offspring would not display ‘elven traits’, which we will assume refers specifically to pointed ears, because things like being shorter of stature, having a genetic predisposition to a smaller body type, larger eyes etc are all traits potentially possessed by humans in Thedas as well.
With this in mind, we also have a few other facts: all elven children have tapered ears, it is a racial trait. They are genetically similar enough to procreate with humans and produce viable offspring. We know the elves’ ears cannot be linked to 'magic’ as many have lost the ability over the years. The only explanation for all 50/50 elf/human children appearing phenotypically human, and all elven children regardless of origin having tapered ears is that the gene for having pointed ears is recessive. This means that for it to express visually, two copies of the gene are required. All elves would have two copies of this gene, all humans would have none. In all 50/50 crosses, the elf parent would pass on one copy of the gene to the child, who would appear outwardly 'human’ in all cases.
However, if this child was to reproduce with another elf, or another 50/50 cross, there is the potential for their offspring to have the gene for tapered ears. If a 50/50 cross and an elf reproduced, their child would have a 50% chance of having tapered ears. If two 50/50 crosses reproduced, there’d be a 25% chance of a child with tapered ears. It would also explain why if any 50/50 children continued to live as a human and had no contact with elves people might assume they were simply human, because without coming into contact with the gene there’d be no way of knowing. It also means that five generations down the line two 'human’ parents could have a child with pointed ears and look at each other nervously.
So yeah, if any of those Suranas, Tabris or Mahariels had kids with Alistair? Yeah. Incorporate this into your headcanons ;)