"If the fidyah becomes obligatory upon a pregnant or nursing woman because she broke her fast out of fear for her child, is it obligatory from her own wealth, or from her husband's wealth?"
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
The fidyah (ransom/compensation payment for breaking the fast) is obligatory from the wife's own wealth, and is not obligatory upon the husband unless he voluntarily chooses to pay it on her behalf.
It is stated in Mughnī al-Muḥtāj (Vol.2/P.174): "If the two [the pregnant woman and the nursing mother] fear for the child alone — such as a pregnant woman fearing miscarriage, or a nursing mother fearing that her milk supply would decrease, thereby endangering the child — then both the qaḍā' (making up the missed fast) and the fidyah become obligatory upon them, to be paid from their own wealth." And Allah, the Exalted, knows best.
I`m keeping a plot of land (10 Dunums) for my children. Is it liable for Zakah?
Praise be to Allah, The Lord of the Worlds.
Land that is purchased with the intention of ownership and personal benefit—meaning to retain it for use and not for trade—is not subject to zakāh, as such property is not considered from trade commodities (ʿurūḍ al-tijārah).
It is stated in Al-Ḥāwī al-Kabīr:
“If it is property and one intends it for trade, then zakāh is due upon it; but if he intends it for personal possession, then no zakāh is due upon it.” And Allah, the Exalted, knows best.
Is it permissible for the guardian to give Sadaqa (voluntary charity) from the money of the orphans?
It is impermissible for the guardian to donate from the money of the orphans because he is entrusted with the safekeeping of that money, and is prohibited from donating it.
Is it permissible to trim the eyebrows if they become excessively long?
Trimming eyebrows is permissible if they become excessively long, yet; it is reprehensible. And Allah Knows Best.