You won't likley find a used engine worth messing with for your car, just fix the one you have. You will love the mpg when its running again, the HP is not there its like 68hp or very close to it. If your engine is indeed the 12 valve carbed HF engine (D15A2 on mine), I just did the head gasket on one about 2 weeks ago. Since you will be removing all of your belts to get the head off, put all new on and like you said a new water pump (you get Honda parts if you want, avoid economy belts.. especially the timing belt). The 1.5L OEM headgasket is not terribly durable, I used a Victor Reinz which had much more metal around the cyliders especially in the hot spot between the 2 center cylinders where they are prone to fail. Got it from NAPA, the head set is about $85 and you will want many but not all of the gaskets in there. The hardest part was getting the aluminum block clean without contaminating the cyliders, the head went to the machine shop for test and surface. Anyway the head gasket fails because of high temp, I would consider a modest investment of about $300 for replacing cooling system components (Thermostat, hoses, pump, radiator, and of course fresh coolant) cheap insurance to keep your new gasket from blowing. If you take your head to a machinist (I strongly recommend you do so that you know the work you do doesn't need to be repeated a week later), give them the valve seals and cam seal from the headset, they will be pulling your cam anyway and may charge a bit extra or nothing more to do that work. Have them check and replace your exhaust studs or do it yourself, they fail (I had 2 broken) and it sux to be finishing the job up only to snap a stud at the end putting on your exhaust manifold.
You will need to remove your exhaust manifold and for me that meant taking the cat off because they are bolted to each other and the manifold brackets are not accessable until the cat was off. after you get the exhaust man off you will have easy access to the water jacket (block) drain plug. Leave the intake manifold bolted to the head until the head gasket is broken free, then just unbolt it from the head and leave it in the engine compartment. You will have to unbolt the intake manifold from a bracket on the back of the block before you will be able to move it or the head.
Change your PCV while the intake manifold is loose, its a real pain otherwise. Other than oil + oil and air filter I would say do the cap/rotor, plugs (ngk or denso only) and wires... catch the fuel filters (2) while your at it. Dont forget to check/adjust the valves at the end. If your Bro is like mine, none of that stuff got done
Good luck, hope this helps