If this helps, here's a few links I saved over the years when rebuilding a few old boats.
The rivets used in aircraft are the same type used in most boats.
Most aluminum boats have 3/16" rivets with the occasional 1/4" rivet.
Loose fitting rivets must be drilled out to the next size.
When measuring how long the rivet needs to be the general rule of thumb is that the amount of rivet shank that you want sticking out before 'setting' the rivet is equal to the width of the shank.
Longer rivets can be cut down, this is fine if you only have a few to deal with but its too time consuming in any serious number.
Rivets must fit tight before being set, if its loose, re-drill the hole to the next size and get the correct rivet for that size. .
Riveting kit
https://www.eastwood.com/solid-rivet-kit.html
(These are fairly expensive, you can use any short stroke air hammer and the rivet set punch and anvil can be had separately).
Solid Rivets
https://www.aircraftspruce.com/categories/aircraft_parts/ap/menus/ha/rivets.html
https://www.wicksaircraft.com/shop/ms20470-universal-head-100-solid-rivet/
https://www.clipsandfasteners.com/solid+rivets
Rivet Nuts (Nutserts, Rivnuts)
https://www.amazon.com/Stainless-Button-Washers-Threaded-Nutsert/
Rivet nuts are notoriously weak and prone to failure. They come in aluminum, stainless and carbon steel. The issue of galvanic corrosion comes into play with these in all situations. SS is the best option.
The problem is finding a reliable source for thee in SAE thread. Most better sources seem to only have metric sizes, and finding SS metric bolts and screws in the US can be an issue.
Harbor Freight also sells a cheap rivet nut kit that comes with a decent tool to install these.
Closed end 'Pop' type rivets
https://www.rivetsonline.com/blind-rivets/closed-end-blind-rivets
These are fine for quick fixes but I don't see them as a permanent fix.
Rivets generally don't need to be sealed but a bit of 3M 5200 sealer around the rivet before setting can guarantee its leak free, just the sealer doesn't inhibit the rivet from being fully set.