Alpha cutoff on billboard component

[anonymous_user_0efc3f0f]

I’m trying to create a series of camera\view aligned objects which i can assign a texture to. I’m doing this via a ForLoop and AddBillboardComponent in Blueprint - pretty simple…except that when I try to assign a texture with an alpha to the sprite used by the billboard via SetSprite, the alpha get cut off.
Blueprint:

Results in viewport:

So I make a material using the texture properly:

and try to assign it to the billboard components via SetMaterial node. But when I re-compile the Blueprint, the billboard components disappear from the viewport entirely. No errors in the output of any kind.
Blueprint:

Result in the viewport:

So my questions are:

1. why can’t i use SetMaterial node on a billboard?
2. more importantly - why is the alpha being cut off of the texture when I assign it to the billboard via a SetSprite node?

Thanks in advance!