Well it depends on your parents/her parents as well. Some people will think that marriage is not complete without the wedding dinner. The dinner is for both host to tell everyone that they are legally married.

Not sure how much you have in savings but from the way you are mentioning is not logical. You want to save up more for the dinner but you want to spend lavishly now, 5k for the engagement ring and 5k for 6 tables, 10k for the dowy.. Are you sure you can save up enough for the main function after 1 year? Estimating the cost, 5k for 6 tables, if 40 tables, it will be easily close to 35k.

Pre-wed shoot usually have to be done before ROM, her ji mui/relatives/friends will surely ask about the photos you guys took once you guys are married is known to them.