welcome to fsi
your not to far from me
cant really help with some of your problems
but i'll give it a go 
, but some of the issues it has dont seem that hard to fix*Bulb on O/S main headlight is easy, just remove a little rubber seal from the back of the head light, un-clip the bulb and replace and then re-fit rubber seal
*N/S, O/S front brake pipe corroded - maybe look to replace both front bake pipes with braided items?
*O/S rear brake pipe corroded - think my fez had this and iirc all my mate did was rub down the brake line to remove the surface corrosion and paint it/grease it up again or as per the fronts buy a whole kit and replace the rear brake lines with braided items as well! do you know if its the main line from the front to the back? or the line that connects the main line to the rear drums?
*Seat belt anchorage N/S requires welding - you or your mate handy with a welder?
*N/S front brake binding which is causing ABS warning light illumination - didn't think Si's had ABS? unless it was an option extra?maybe worth just replacing that caliper and see what it does then?
