The second question: you can change the owner of the original house first, so the new house allocated after the house demolition can be your two brothers respectively.
The third question: regarding your current property division, it should belong to the property your parents gave you, mainly through tripartite consultation. Write clearly the rights and obligations of all parties in the final agreement.
Fourth question: First of all, if your parents' names are written in another set, they can be used as inheritance in the future. In addition, like the above reason, the house belongs to parents, and how they distribute it should be completely according to their own wishes. There is no legal requirement that parents must give the house to their sons.
Fifth question: It is better to write parents' names. Of course, in order to avoid inheritance tax, according to the second point, as a gift contract, conditions can be attached, that is, the son undertakes the obligation of raising, and if he fails to fulfill this obligation, the gift will be invalid, so that the rights and interests of parents can be protected.
The hardest thing to repay is kindness. I hope you can solve the problem properly, be kind to your parents and your loved ones.