I didn’t know about the points, but I had redistributed them anyway before imbuing.
You definitely can use a crystal of remembrance after imbuing. It’s the only way to increase the number of legacy if you imbue before reaching lvl 30, as there is no reforging process. It might be even better in case you don’t have the legacy you want ready to place in the open spot. I couldn’t find the legacy I wanted from deconstructing 3rd age weapons. I could have get it from the store, but it’s 500 TP. So I use the crystal after imbuing, and I had the choice of any possible legacy available for the item.
Getting the right legacies in the old system can be quite a pain, or you need to use TP to buy them.