2) spinnaker pole track and pole fitting on the forward side of the mast. (the location for this may be on the fleet drawings)
3) spinnaker pole ("pole" for short);
4) spinnaker pole lift (halyard for the pole)(sometimes mistakenly called a "topping lift", which is really the line which holds up the outer end of the boom). For the full-race treatment, the tail of the pole lift can be lead back to the cockpit.
5) spinnaker; (also called the "chute" - a shortened form of the old term "parachute spinnaker")
6) at least one spinnaker afterguy (often shoterned to just "guy") to pull the pole aft, a spinnaker sheet, and a foreguy (to pull/hold the pole foreward & down) Two sheets and guys are preferred to rig for gybing the "chute". The afterguy is usually heavier (thicker/stronger) than the sheet, but two guys would sufice if you wanted gybing at least cost;
7) at least 2 snatchblocks (one for the sheet, one for the guy) to go on the rail to lead the lines aft to winches; 4 are better, so you can rig for gybing (if racing);
8) a snatchblock or other block to rig the foreguy. (A Full Monte installation would lead the foreguy aft to a cam or clam cleat on the cockpit combing.) Access to a winch is usually not needed for a foreguy on an I-36.
9) if serious about racing, I'd suggest 2 double turning blocks at the aft end of the rail so sheet/guy snatchblock leads can be easily moved fore and aft for optimum performance; these also result in a consistent lead angle to your winches.
It is easiest to hang the halyard and pole lift on the outside of the spar, but the dedicated types would insist on them being inside the mast to reduce windage.
An additional thought if you are only planning on cruising, is to order your spinnaker with a "sock" which is a tube of cloth that can be pulled up and down with a continuous line. This makes it much easier for two people to set and douse the chute. Since it somewhat reduces sail area and the shape of the head of the spinnaker, it is not used for serious racing (except single handed racing!).
Again, in the die-hard category, the pole fitting on the mast can be rigged with lines and lead blocks back to the cockpit so the inboard end of the pole can be raised and lowered by the cockpit crew. This keeps weight off the foredeck, and it is often necessary to raise the inboard end way up when doing a dip-pole gybe so the outer end of the pole can clear the headstay and be above the lifelines.
All of the go-fast items above can be added after an initial setup to keep first costs down, with one exception. A fixed pole attachment fitting can be put on the mast which is cheaper than a track and sliding fitting. This will make gybing more difficult, and limit how you can adjust spinnaker trim, but if you only want a spinnaker for cruising, it is a simple solution. The fixed fitting and its installation would be the only throw-away investment if you later went to a racing setup.