Its totally your call, I'd strongly suggest you go for it, It will always give you detailed reasoning about your refusal, which you can address later on, forget the 90 days, It's an exceptional case, you have to see how much you can improve your representation, Instead of relying on mere assumptions. There is a huge sum of money at stake, so just go for it
For SDS, I am unable to guide you on the fee, there can be two options, either you ask the college to get you an invoice for the 2nd semester of UTP and the 1st semester of the Degree (combined) and then proceed with payment.
OR
You already have paid full fee for the 1st semester, so you can actually proceed with the payment of the 2nd one and show the receipt of both the semesters out of which 1 has been already completed (or is near completion)
Not sure which option suits you best, might work either way
It does matter who you show as a sponsor, you should be careful with the evaluation, get it evaluated from professional evaluators that are verified by PBA (Pakistan Banks Association) because the Embassy would then be satisfied because it is a credible source to them.
Make sure you show your source of Funds concretely and provide them Bank Statements with Cover Letter.