IMHO any rebuilt or new water pump will work fine. The aftermarket folks do a good job of solving problems you don't actually have.
Leave the oil pan on unless for some reason you want to take it off. Make sure you remove the 3 bolts at the front of the pan the go into the front cover. The gasket sets for a front cover job will most likely come with a short segment of cork oil pan gasket to replace the often ruined stock one. Cut the original one flush at the block surface and substitue the new one. My stock gasket is rubber and was fine and flopping around after I pulled the cover off. As I outlined above I used dental floss through the bolt holes to hold it in place when I put the cover back on. My original gasket is still in there doing its thing. Overall there is no need for a timing cover job to require pan removal.
One tip you might try is pull the water pump off leaving the cover on the engine. I jacked up the rear axle as high as my jack could go to spill out all the coolant I could from the block. Drop the rear down again and pull off the engine cover, you will get less or even no coolant falling out of the block face. With the cover off coolant can fall into the open pan lip in with the oil and I really wanted to avoid this. I got just a few drips in the pan this way.
Leave the oil pan on unless for some reason you want to take it off. Make sure you remove the 3 bolts at the front of the pan the go into the front cover. The gasket sets for a front cover job will most likely come with a short segment of cork oil pan gasket to replace the often ruined stock one. Cut the original one flush at the block surface and substitue the new one. My stock gasket is rubber and was fine and flopping around after I pulled the cover off. As I outlined above I used dental floss through the bolt holes to hold it in place when I put the cover back on. My original gasket is still in there doing its thing. Overall there is no need for a timing cover job to require pan removal.
One tip you might try is pull the water pump off leaving the cover on the engine. I jacked up the rear axle as high as my jack could go to spill out all the coolant I could from the block. Drop the rear down again and pull off the engine cover, you will get less or even no coolant falling out of the block face. With the cover off coolant can fall into the open pan lip in with the oil and I really wanted to avoid this. I got just a few drips in the pan this way.