Ben, Regarding your pump. Your first concern is to stop water from entering the boat. After that your existing pumps will do the job. Sure, if you have the room, why not have lots of pumps. The problem is having enough people to operate the pumps. So have as many as you have crew…of course, at least one should be electric with a float switch. Think about this…
Regarding the Danforth anchor. You will only use a stern anchor in a direct line pull, you will not be swinging 360 degrees on this anchor. So you can use the Danforth, it really holds well in the straight line but I do not advise using it for your primary anchor. If you want my opinion on anchors, email me direct.
I totally disagree with leading any stern anchor through a hawse hole or any other hole unless it is led back out. Worse is to leave the excess anchor rope in the lazarette and lead the rope out through a deck pipe. I have had many bad experiences using stern anchors and believe that it is an anchor that should be able to be released from the boat in an instant. Please read page 207 in my book about why I feel this is so important.
I store my Danforth stern anchor on my boomkin when gunkholing but not passage making. I do not have it attached to the chain unless I feel there might be a need to use it. I keep the short length of chain and 200+ feet of rope in a sailbag in the lazarette. When I think I might use the stern anchor, I attach the chain to the anchor (swivel). After the stern anchor has been deployed, I stuff all the excess rope in the sailbag and hang it on the outside of my sternrail (pushpit). I DO NOT LEAD THE ROPE THROUGH ANY HOLES. If I need to get away in a hurry, I cast the rope off the cleat on my boomkin and throw the sailbag overboard. Oh, I do have a float with a snap that I can attached to the sailbag to retrieve it later. I would rather have to dive on the anchor later than take the chance of catching my prop on the anchor float.
Since you will only use your stern anchor for preventing your boat from swinging, it can be a smaller anchor with only about 20 feet of chain. If you only use this small anchor for stern anchoring, then you should have a heavier anchor you can use for emergencies like Kedging off, etc.
For me, the minimum anchors a boat should have is the primary anchor which can be used when the boat is swinging 360 degrees. A secondary anchor that has equal holding power as the primary. If you ever lose the primary in coral or rocks, this secondary anchor will become your primary. Then a smaller stern anchor.
On my own boat, I have my primary set ready to go on all chain. I have my secondary stored on the side of my boat, attached to chain and rope, ready to go. I have a third anchor that can replace the secondary or primary and enough chain and rope to do the same stored in the lazarette. Then I have my stern anchor which is smaller and easier to handle. I encourage you to put your efforts into good anchoring hardware. Your chances of losing a boat is not at sea but at anchor.
Roger