I will not pretend to be a metallurgist, but I did study and practice it while I was working as an engineer. I'm much better at tribology, a skill you must have if you aren't great with metallurgy
I would not soak the boat. The current dryness of the hull has halted the dezincification.
For the process to begin again all you need is moisture to combine with any salts that remain trapped in the wood.
Salts will not flush from the wood. Salts have entered into the wood in the places where the wood has been penetrated (the tack locations). Introducing water will re-start the decay.
The blooms you see are indicators that salt has decayed the tacks. The question that needs to be answered is how badly?
If you did not need to do other work on the boat you could prevent further decay of the tacks by keeping them dry.
Soaking is exactly the opposite of what you should do.
If you could seal the hull inside and out it would have the affect of preserving the metals exactly as they are.
Of course that does not align very well with what you might want to do to spiff up the hull.
You will want to wash it with a soft brush and TSP. You might want to strip the varnish. You may want to TSP again and also give it a wash with Teak-nu. All of these steps involve water and the last one involves an acid. All of these are possible triggers to restart the decay of the tacks.
Don't sweat it. Before you do any of this you will test a few of your tacks to determine the extent of the damage. Planking and ribs rarely get completely soaked through so the blooms that you see may only be highlighting decay near the surface of the wood. Once you are certain that the tacks are in reasonable shape (worry about them if they are brittle) you can carry on with finishing the hull for recanvasing. Take your time once it is stripped and be sure that it is really dry before you apply good quality spar varnish on the inside and a sealer on the outside. A warmed blend of mineral spirits, boiled linseed oil and turpentine works well for this. Some use spar varnish on the outside of the hull. Considering the need to prevent further damage to the brass (by sealing it from moisture) you might want to consider this for your boat.
The key at this stage is to determine the extent of the damage to the brass. You can find out quickly by picking a couple of the worst looking ones to pull out or to re-clinch. Pulling them will allow you to see how extensively they are corroded. Clinching them will tell you if they are brittle.
If you are lucky you might not need to do anything special. If you are not lucky you might need to replace large numbers of tacks. I have heard of folks replacing over thousand tacks on a bloomed hull.
WRT soaking the entire canoe to remove the glass, I have tried that once. I have not done it since. If you do decide to soak it, I would suggest that you remove the decks and thwarts before you do. These bits do not enjoy being submerged. Also, expect the boat to weight a ton when you try to pull it back out.