Zakat on Insurance is payable once the surrender value reaches the nisab for the year in concern. This is because the surrender value is the amount that one is able to obtain and use in principle.
Currently, Zakat on Insurance is only applicable for Insurance in the form of savings endowment - where the intention is to grow the wealth in savings. Hence for your situation, there is no Zakat for all 3 of your insurance plans.
If the jewellery is intended for use, Zakat is not due on it as the weight is below the uruf of 860 grams. If the jewellery is not intended for use, it is obligatory to pay Zakat on it once it reaches the haul, as the weight has reached the nisab of 86 grams.
I have a combination of savings, shares and insurance. Do I sum them up all, check if it exceeds the nisab, and if yes, I take the net values then times 2.5%? Or do I do the calculation individually on each asset class?
The Zakat for your savings, shares and insurance is calculated separately and not summed up together before performing calculation. This is because the calculation method for each is different:
Zakat on Savings: Based on 2.5% of lowest balance in year if this balance does not fall below nisab value.
Zakat on Shares: Based on 2.5% of total market value of shares owned at the end of year if this value does not fall below nisab value.
Zakat on Insurance: Based on 2.5% of the surrender value when haul and nisab are due.
Zakat is obligatory (wajib, one of the pillars of Islam), has specific rate of 2.5% and minimum level (Nisab), specific period of fulfilment (Haul) and specific beneficiary (Asnaf). Sadaqah is encouraged (sunnah), has neither specific rate nor minimum level, specific period of fulfilment nor specific beneficiary.