ᐅ Purchase of a Property with Existing Structures; Future New Construction Planned

Hello dear community,

We will soon be purchasing a plot of land with an empty house (approximately from the 1950s/60s) and plan to build a new house there in the medium term.
For now, the property will remain unused for about 2-5 years to allow for further savings of equity and due to my wife’s current employment situation (currently on parental leave; a permanent job is required for the mortgage).
I have a few questions and would appreciate your experiences and advice.

(1) Tear down the house immediately or leave it empty: What are the risks and obligations if I demolish the house right away or leave it vacant? What factors should I consider? How would you proceed?
(2) Under what conditions could it make sense to rent out such an old house again? (With manageable renovation) My common sense tells me this would cause more hassle than benefits: obligation to renovate, energy certificate, new heating system, termination of lease for new construction, etc.
(3) If I demolish the house immediately, what should I do with the basement? We want to build without a basement. Would the excavation be filled and compacted with F1 sand? (The new build will also be significantly larger than the existing building)
(4) Could it make sense to set up a permanent construction water supply immediately after demolition? Background: If the water connection is inactive for more than one year, it is removed in our district, and I would have to pay over €10,000 (ten thousand euros) again for the street connection during new construction.
(5) Related to (4): Is it possible to arrange a longer-term temporary construction electricity connection? This would be necessary to heat the construction water supply in winter and to have electricity on site if needed. Renting construction power boxes with monthly inspections would likely be very expensive. Are there alternatives?
(6) Achieving cost savings on the house build through a long planning horizon: What options do I have to reduce costs for the new build by planning over a longer period? Are there any tips on how to make this disadvantageous situation work to my advantage?
(7) Using or monetizing the undeveloped plot in the meantime: Are there ways to make meaningful use of or even monetize the undeveloped land during this interim? If construction electricity and water supply are available, could the garden be used or maybe even leased?

Thank you in advance for your help and advice!