Hi Rainne,
I was in this panicky and confused state about 1 month plus ago because i couldnt decide on the BS and was analysing all the different packages. For me, i limited myself to about 5 BS and in the end was just a matter of deciding between 2 BS.
No, it is not cheaper to take MUA and flowers outside. In fact, if you ask them to 'take' out those items, the amounts that are deducted are less than what i have to pay outside. The reason why i removed both MUA and flowers is because i have my own hair stylist whom i have been going to for a long time who also does make-up and i am very comfortable with him. And, for flowers, it is because i am trying to use a deposit that i very stupidly placed at another BS (in the initial stages of searching for a BS).
When i was shopping around, i originally budgeted an amount of $5K (for the whole package incld photography, etc). Upped that to about $6K after i went round to TedWu and SiL. But, realised that additional photos (if we do select them) for the wedding album will add another layer of costs. So, we are sort of prepared for the additional costs for the photos....but not sure how much we will pay for them. We will see when the time comes.

If you dont increase the no. of photos, you should be able to limit your costs. Some people manage to do so by being very disciplined.
I paid $1800 for O Studio by signing up with them directly. The only reason why i think it is better is because you get to negotiate with them for the no. of photos, type of albums, etc. etc. O Studio is definitely not cheap but i love their work. So, you need to explore your options. I was actually considering between O Studio or Utopia.
I hope this helps. Let me know if i can help any further. I understand, in fact i am sure we all understand what you are going through; as we have all gone through it.