Tight deadline! But I understand the pressure under which you are!
Charles Ferrar is probably best placed to advise you as he has a cruising Hartley already; however for what it’s worth, here goes:
1. suitable cruising sails with reefing points
with a new boom you may already have in boom tackle for at least 1 reef, but 2 sets of reefing points on the main would be more than desirable.. your local sailmaker should be able to oblige, there was a discussion here http://wayfarer.org.uk/forum/viewtopic.php?t=459&highlight=reef
regarding relative sizes. Various arrangements at the tack but you could adapt your cunningham by attaching a suitably sized SS Hook to it.
I’m a long way away, but if you’re desperate I have a spare cruising main you could ‘lend’!
2. jib furling gear
Best tackle is Harken (High load) as you will have high halyard tension in a racing boat. You can use the Helyar reefing system with this to reef your Genoa (you will have a dangerously unbalanced boat if you try to sail with full genoa and reefed main) but it really doesn’t work until you’ve furled at least 4 turns (storm-jib size). You should make sure you have some method of preventing ‘forestay wrap’ when furling – either Disc on the halyard or triangle with hanks on the forestay.
3. outboard engine (we have an fitting for this attached to the transom)
2-2.5HP 2 or 4 stroke – New Suzuki 2.5 4 stroke street price £349 ish many use Honda 2.3HP slightly more expensive, but use anything that works!
4. anything else you think we might need.
definitely an anchor, folding grapnel will do but CQR or danforth better – the Alloy Fortress anchors are very light for their size but you must >=2m chain with any of them.
A decent paddle, oh, and you may need to seal your stern flaps – ask Charles about this.
A decent Rudder uphaul and downhaul with a safety kickup.
I think that’s it – if anything else comes to mind I’ll post it!