the tank should work fine. people build these things all the time and then you can also buy them prebuilt. Your best option IMO
would be to learn the what/where and why your sump is like it is by learning how they work in general. This forum is a great place to start and learn. A few hours here and some of the websites that are linked in this forum will serve you well in your new tank setup. You can do a forum search for "Sump setups" or "how a sump works" or other key words and you will be well on your way. Worst case you can use the holes for a canister filter and get rid of the sump?
If the above dosent work for ya ask the question again in the other parts of the forums and you will get more info.
welcome back and best of luck