Around the Jewish Year

Hello Rabbi, Happy Chanukah!
I would appreciate guidance on a somewhat complex halachic question.

I harvested 100 kg of olives for oil production:

80 kg of them were hefker (ownerless),

20 kg belonged to someone who gave me permission to harvest them.

When I arrived at the olive press, I was told this was too small a quantity to process alone, so I waited for someone to join me. Another person arrived with 50 kg of olives, and oil was produced from a total of 150 kg. We then divided the oil according to the percentage each of us contributed.

A. Of the oil that I received, from how many kilograms must I separate terumot and ma'aserot — from 150, 100, or 20?
B. Do I need to coordinate with the other person whose oil was mixed with mine? I understand there may be an issue of bilah belach, that liquids mix.

I received a bottle of olive oil from a farmer friend without kashrut certification. The oil is of excellent quality and intended for consumption. I refrained from eating it due to kashrut considerations. Is it permissible, lechatchilah, to light the Chanukah menorah with this oil? Does the fact that there may be kashrut issues render the oil unusable (i.e., should it be discarded)?

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Whoever sees especially beautiful creations recites the blessing shekacha lo ba'olamo; "Who has such things in His world."
Whoever goes out to fields or gardens in the days of Nissan and sees trees blossoming and budding recites birkat ha'ilanot, the blessing for the trees: "Blessed … who has withheld nothing from His world, and has created in it beautiful creatures and trees for human beings to enjoy.'"  What is the difference between both blessings?

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