Yes

Summon Lesser Demon:

a vial of blood from a humanoid killed within the past 24 hours

It does not say it has to be dead at the time of casting.

It does not even say it has to be dead at the time of collection, but I think that was the intent.

Balance Considerations

This spell is a bit weaker than Conjure Animals.
What arrives is on the same power level, as the summoned creatures have same CR. However with Conjure Animals you have more control over what you get, and what they do.

So for balance the components of Summon Lesser Demon should be less restrictive, not more.
For me this means whatever workaround or shortcut you can take you deserve it.

RAW only things with a Gold Value are costs

The spellcasting rules on components state:

A character can use a component pouch or a spellcasting focus in place of the components specified for a spell. But if a cost is indicated for a component, a character must have that specific component before he or she can cast the spell.

You cannot replace material components that have a listed cost however.

What is an indicated cost?

By RAW a cost is only for components with a gold value. For example, Identify has the unique costs:

A pearl worth at least 100 gp and an owl feather

In this case the owl feather can be replaced by the focus or component pouch. While the pearl cannot as it has a gold value cost.

How does the component pouch/spell casting focus replace the components?

The spellcasting focus does exactly what it says, it provides a focus for the caster to channel their magic through. The assumption is that without their focus they need much more complicated components that have some relation to what they are trying to do. See What is the point of inexpensive material components? for relevant information.

Could a unique requirement be considered a cost?

Certainly, if your DM rules it that way. However this is not RAW and we don't have enough information to know if it is RAI.

What would happen if it was ruled this way?

Your casters would have to work a lot harder for their magic. This isn't necessarily a bad thing. The number of spells with these unique requirements isn't that many. This could be a great opportunity for roleplay in obtaining the acquisition of them.

At then end of the day the answer is "Up to your DM" as with most rules based questions.

How would I rule it?

For requirements that could be fulfilled by any number of items, I would allow the focus to replace it. This covers your first example. As there are hundreds of things a creature may find distasteful.

For time limited requirements, I would rule they cannot be replaced. As you point out they are unique constraints and particularly the one you quote could raise questions as to how it was obtained.