So... obvious preamble... we don't actually have any examples of this sort of engineering, nor any research on anything like it. Splicing in genes from one species into another obviously works (see Bt corn, for example) but that doesn't make a proper Dr. Moreau style hairy, angry, human-animal hybrid. So, y'know, just wave those hands and say a
wizard sufficiently advanced genetic engineer did it, and everything will be great. Whatever you do, don't go into details of the techniques used, because that sort of scifi will zeerust like nobody's business. Don't even think about mentioning CRISPR.
With that said, lets move on.
Lets assume you've just thrown in a load of stuff from a selection of nocturnal mammalian predators, and maybe got rid of a load of boring human genetic load at the same time (unless you weren't requiring your species to keep its useful traits for more than a few generations, in which case feel free to throw in as many genes as you like, as who cares if they all break in the future?)
stronger and faster than the average human
That's easy enough. Depending on how you define average, 50% of humanity is stronger and faster than the average human.
Just, y'know, exercise. You don't really need genetic engineering to give you this.
Avoidance of sunlight and bright lights, and more active during the night.
Nocturnal vision adaptation might be associated with dislike of bright lights. Pupils that don't constrict as far as regular human ones, for example, but there are other kinds of hemeralopia you use as inspiration.
Maybe they could be weak to fire
You're weak to fire. Everyone is weak to fire. Animals get cooked. Stay away from the burny things.
They have cannibalistic tendencies and specifically target humans as their food source
They ain't really human, so they can't be cannibals. Just predators. Humans don't have any surviving natural predators, so not many things can be said to have a taste for humans. This might just end up being an unfortunate coincidence, what with starting out with a nocturnal predator base and having them effectively hunt humans, and all.
Maybe humans just taste really nice, like high quality bacon. Maybe you'd be joining in, if you knew...
They are the carrier of an unknown but deadly virus that very few normal humans are immune to
Aha. Now, this you can get from endogenous retroviruses that come from genes takes from other species, or organs transplanted from them. Most ERVs are fairly inert or even broken, but the process of engineering your critters could have inadvertantly fixed them, or the interaction of the spliced in genes with other things such as regular human transposable elements or other retrovirus reactivated them. May or may not be bad news for the carrier, potentially very bad news for both humans and the donor species, given the virulence of things like HIV.
Poor vision but very strong smell and hearing
Now, poor vision doesn't play at all well with the "nocturnal predator" vibe. Most carnivorous nocturnal predators with mammalian prey have pretty good vision. Might not be colour vision, of course, and there may be the possibility of other odd optical effects caused by the pupil dilation issues I mentioned earlier... large apertures are associated with a shallow depth of field, for example, and any focus issues would cause blurring that would be tricky to correct with glasses.
I'll assume better sense of smell and hearing come with the rest of your genetic engineering magic, so you can handwave that as you see fit. It isn't like there's real life xenogenetic splicing to take as an example, yet...