It is hard to come by endmills for wood where I am at as most say thery are for aluminum, etc. Are there any downsides to using such endmills for wood projects? Or is it a matter of adjustments of feedrates?
Yes, one adjust feedrate and speed to create the chipload which is appropriate for the material which you wish to cut.
You should however be able to use router bits which are pretty readily available: https://www.shapeoko.com/wiki/index.php/Endmills#Router_Bits
It will generally be pretty hard these days to find endmills specifically for wood. In general, whatever you get will work fine with wood. The exceptions are around the really exotic, really hard woods, and those need a little more effort anyway. As Will says, router bits work fine in the machine too.
Some exotic wood dust is toxic, don’t remember which ones.
Actually, even woods which are ostensibly safe for food contact are not healthy to breathe in as dust, and there are surprising toxicities and concerns for wood dust beyond the basics of not wanting to breathe it — cherry is poisonous to horses for example, and black walnut is that and aleopathic (will inhibit plant growth).