One of the conditions of Hajj being obligatory is being financially able (i.e., has sufficient provisions to get there and back, and that should be surplus to what he needs to spend on those on whom he is obliged to spend, until he returns from Hajj).If a person has saved enough wealth for hajj but then chooses to spend it before hajj in order to make himself no longer meeting this condition thereby to delay it, is he sinful? Also, is it permissible to save until he has enough wealth to spend on hajj and for his future spouse, rather than immediately for himself (so as to not delay hajj)?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.

The scholars differ regarding the obligation of Hajj, whether it is an immediate obligation or can be delayed. Those who consider it obligatory with flexibility in time, such as the Shaafi'i school, have no objection to what you mentioned. They do not see any sin in postponing Hajj even if one is capable of performing it. As for those who consider it obligatory immediately, they are of the view that the crucial time is when people start going for Hajj. If someone possesses the means to perform Hajj during that time, it is incumbent upon them to promptly undertake the pilgrimage. If they spend the money before that time without the intention to evade the obligation of Hajj, then they are not blamed for that. However, if they spend the money to avoid the obligation of Hajj, it is considered a trick, and they risk sinning, as using tricks to evade religious duties is considered forbidden by many scholars.

As for your second question, it is recommended to resend it as a separate inquiry with additional clarification, as it appears to contain some ambiguity.

Allah knows best.