Just for clarity, when the epilogues come out at the end, you will get an option to marry most characters normally, without any kind of contract tied to them (assuming you did other things to establish a relationship). So if you want to marry someone without a contract, that will eventually be available at the end.Yeah I agree and as mentioned I didn't do it at first since I was going for a love route, but basically if you wanna marry them you need to do a marriage contract with them and at the same time as you do a marriage contract you do the property part as well, so if you do the property part first and then upgrade it to a marriage contract it doesn't really matter in the end since you'll do it anyway. But yes I think it's a very strange thing to make the marriage part include turning the girls into your property. It also max out the "love" but at that point you might as well wonder if your brainwashing / forcing the love through the contract.
But again in the game if you wanna marry them you have to turn them into your property as well anyway.