Should the entire equity be contributed in property financing?

If now a 1000 euro installment is applied for 100k, how high should the installment for the house be later?

One thing has nothing to do with the other.

I would also contribute the existing equity capital now, provided that it is also intended to flow into the project later and is not used for furnishings, etc. It improves the conditions and saves interest.

Why should one have anything to do with the other? If he decides now, he is bound to the bank. Or do you think someone will finance his house if he is in 2nd place on the ranking? Paying off early will also be more expensive, etc.

The home loan is to be renegotiated, the repayment can be newly determined.
In addition, this concerns short-term or even variable loans. This has the advantage of being able to look for a new partner for the large loan without major costs.
Last but not least, a prepayment penalty depends, among other things, on the outstanding debt and the remaining term. It should be manageable.

That is why I mentioned financing without a mortgage. This exactly avoids this dependency and the back and forth with the land registry office, which demands payment every time.

If you set a rate of 1000 euros for 100k now, how high should the rate for the house be later?

Why, I can renegotiate everything in the new loan anyway.

Why should one have anything to do with the other? If he decides now, he is bound to the bank.

Or do you think someone will finance the house for him if he is in second place on the ranking?
Paying it off early will also be more expensive, etc.

With a variable loan, I am not binding myself to the bank right now. After any period of time, I simply refinance, and the new bank will be registered first in the land register while the old one is removed.

The house loan has to be renegotiated, the repayment can be newly set.
Moreover, these are short-term or even variable loans. That has the advantage of being able to look for a new partner for the big loan without major costs.
Last but not least, a prepayment penalty depends, among other things, on the remaining debt and residual term. It should be manageable.

There will be no prepayment penalties as I will either take a variable loan or one with a short fixed interest period.