That list and timeline should be no problem at all...
As for the air filter, with your fab skills, I think a single filter with a nice custom box around it would do nicely.
Pros:
1. Quicker replacement / cleaning
2. Easier to build box for it
3. Less "cluttered" engine bay
4. Less weight (you could potentially reduce the piping without affecting performance)
Cons:
1. Less surface area for filtration (correct me if I'm wrong, but it looks like if you measured the two vs the one, two has more surface area)
2. Time... you only have 94 days
3. Single POF (point of failure)
Thats my two cents on it. If it were me, I'd probably keep the twin setup.... for now.