Secondly, if his parents want to be judgey - that's up to them. Don't let it affect what you choose for your day. If you are worried that they will moan, just don't tell them what you are planning - tell them it's a surprise. Hopefully, they won't be rude enough to criticise anything on the day, and honestly if they want to moan to themselves, let them, as long as you have a lovely day.
We're doing a mix of DIY and not - I'm making a lot of the decorations and the invites, plus we are growing our own flowers for the centrepieces.
For us, this is reducing costs, but as the post above says, that isn't always the case, so do shop around.
Our venue allows us to choose our own band/caterers/bar, everything with no commission or corkage fees, which is great, so look around for something like that to give you the most options, and save you from being too restricted.
Hope that helps! X