That depends on your provider. Some funds make the disability insurance a function of the amount saved, and others don’t. For mine, it doesn’t change anything.
I’m no expert but I don’t think this is how it works. You have 15 years to bring your equity to 35%. So when you sign the mortgage, the payments are set so that you fulfill this condition. Whether the property is reevaluated after 15 years doesn’t play a role. Well, what could happen is: you bring your equity to 35% in 15 years, then the house is reevaluated (let’s say the value increased 30%), and then you can get a “reverse mortgage” from the bank, given that you now own 50% equity based on the new value. So the bank could lend you 15% of the value of the house at the same rate as the mortgage.
Withdrawing the second pillar is, in my opinion, superior to pledging because the amortization is less steep. Another point to consider is taxes: pledging is not a tax event whereas withdrawing is. The thing is: since the tax rates are progressive, it’s better to withdraw 2 smaller amounts (one when you buy the property and one when you retire) rather than 1 big one (i.e. to withdraw only when you retire).