T's birthday party

I am going nuts here. With T's first birthday approaching fast, we have to figure out what to do for a party. P and I have never been in favour of celebrating 1st birthdays. The baby not only doesn't know that the celebrations are for him, or care, in most cases it turns out to be torture for the little thing.
Having said that, T has thoroughly enjoyed all the birthday parties he's been to so now we don't want to deprive him of that and we don't mind putting up a small celebration just for our friends and close family.
The only problem is that what started as small is getting completely out of our hands now. I never wanted to be one of those mums who have nothing better to do so they plan their kids birthday parties months in advance but now that there's just a little under a month left, we find we hardly have any choice of venues available. I would love to do a small thing at home but we will surely fall short of space and we can't use the terrace because of the heat.
Another issue with doing it at home means throwing our varied group of friends together and also our family. P and I never drink with our family. It might seem like double standards but it's just that my mum and his parents are quite conservative when it comes to drinking and partying. But this time P and I have decided to come out in the open. Not sure if this would actually happen but we want to. When I told my mum that we want to offer liquor to our friends for T's party she freaked a bit and has since been referring to it as 'drinks party' instead of 'T's birthday party'. So now you know what I'm talking about.
The biggest issue of-course is the guest list. Now I am quite close to most of my extended family.. first cousins, etc.. so I have to and want to invite them for the party. P is out of touch or not on talking terms with most of his cousins. But he says his mum might feel that we've invited so much of my family and none of his. Though it is completely unreasonable considering the relationship he has with them. So all this has been causing a lot of heart burn and we end up cancelling the whole thing thrice a day.
If we go all out (we both don't want to) and call the whole families,etc, etc.. we end up spending a lot more than we intended and we end up wasting our time pleasing the relatives and not celebrating with our friends. This kind of ruins the whole idea of the party. Also this would mean like a 200 people party and how can we do such a celebration in my sister's absence.
The latest plan is to do a small thing at the club on T's birthday and a bigger, more family kind of a thing a month later when sis arrives.
Though pulling it off is not going to be an easy task either. More on that later.