What makes you think it's a February?
I admit it was a miss. I didn't know that October was also called "zhovten" (in Polish that would be "żółcień", a beautiful name indeed), so just by comparing all the months' names to the writing I thought "fiewral'" to be closest. Kudoz to you for this one.
As for Osina - it's a good guess since Osina makes sense as a name of the tree ("aspen") but I've never heard of that name and as you might have noticed there was a horizontal line or two "-" that's how older generation used to mark lowercase т (t - that's where Cyrillic coincides with Latin), it could also be й (j).
Could be "t" but I can't think of any name that would fit then. Besides, "t" in "Kostia" is written as "m".
The fourth letter could be also cyrylic "g".
As for the ending, it's -ji therefore in Nominative would be -ja - and that's fine - before WWII some Polish female names were spelled and pronounced this way, e.g. Zofija, especially in the east of Poland.
So - Osinja, Asinja - ??? Might be some Eastern name. The Eastern Orthodox believers have a lot of names which sound strange to Poles (Eastern saints' names). But I can't Google anything similar.
The name Michalczyk is quite popular in Poland too.
And what's your take on Tyszowce/Tarnawce?