Our financing with "own contribution"

Hello everyone,
the time is almost here - we will soon be choosing a plot of land in a new development area and have been thinking a lot about financing for some time now.
Currently, our situation looks as follows:

He (29): Income 2700 euros net per month
She (30): 1800 euros net per month (plus Christmas bonus)
---
4500 net per month

We have about 40,000 euros in equity (he has only been working for 2 years, the apartment had to be furnished, wedding had to be paid for)

So far it sounds simple...

My girlfriend's parents would like to pay for the plot of land. For this, they would take out a mortgage (is that the correct term?) on their own house and provide us with the money for the plot (about 75,000 euros).

My father runs a heating/plumbing/electrical business. He would like to "gift" us the heating/plumbing/electrical materials and labor costs.
Will this be fully recognized as equity by the banks? On what basis is it calculated, the equity price or the "normal" sales price?

We have roughly estimated the house costs.
160 sqm without cellar, standard equipment, including plot (75,000):
425,000 euros
-75,000 euros plot
-60,000 euros heating/plumbing/electrical (rough estimate, air heat pump + controlled residential ventilation + bathroom equipment)
-40,000 euros equity

= 250,000 euros financing requirement on our side.

Will the plot be fully counted as equity for "us" even though it was bought on credit by the parents?
Will my father's gift/in-house work be counted as equity and if yes at what price? Equity costs or the normal sales value?

What loan-to-value ratio can I calculate with?
Hope someone can help me here...
Best regards and happy Easter holidays

The bank is only interested in the security itself... who pays for it doesn't matter to them. If your parents do not service the loan, they do not lose the land, but their house: so yes, they don't care. The bank should acknowledge the whole thing - however, you should ask the notary you trust about how gifts work - I assume you are both owners in the end. Are you married? Better to clarify everything beforehand, so you don't have to pay anything later. Gifts from parents to children are not a problem - I don't know about spouses. To what extent the bank wants your breakdown of "personal contribution" I don't know in detail - but it should be possible within limits. Loan-to-value ratio then accordingly just under 60% - ideal, therefore.

Just out of curiosity: You're not quite sure how the loan value is determined? You can't determine it from the information given...

Yes, but you are right, a few details are still missing for that. The most important question for me in my original post is this:

Will the gift/personal contribution from my father be counted as equity and if so, at what price? Equity cost or the normal selling price?

Yes, she will accept it... of course you can experience surprises, but usually the bank for new buildings in a "reasonable" location also orientates itself to the price of the house - we even received better conditions than "theoretically" calculated with the crude method (construction costs / (construction costs + land))

Lex, do you know how they roughly calculate that? Our financial broker always acted as if new building price + land + cash = equity capital - so 1:1.