I would love to use water based product but all the info I have read so far does not recommend using it over nitrocellulose lacquer. Have you had any experience doing that?
As far as spraying indoors, I would have no choice but to do that on the face frames and sides. The cabinets are installed and to remove them would be a major operation. Closing off the kitchen and putting a large fan in the window plus wearing a respirator is about all I could do. It is not something I look forward to doing. If I could go with a water based product I would definitely do so. Anybody had experience doing that?
I am by no means an expert on nitrocellulose lacquers (so hopefully others will chime in soon), but given what I do I know of their major health issues I would make the major effort to move the cabinets outdoors for finishing (no fun, I realize). The fumes from most nitrocellulose lacquers are not really something that one wants anywhere near their family, much less themselves, as they are among the most toxic of all the finishing choices based upon my understanding and I am not sure that it is really practical to adequately ventilate a house effectively to make spraying within the house safe without very specialized gear (as well as specialized gear like SCBA if operating in confined spaces with inadequate ventilation while spraying). Sometimes we have to pay the piper, even when it may be painful, when we go back to fix a past mistake, such is just part of the learning process and often makes for some lasting memories that ensure we never make the same mistakes again (many of us have been there, so you are in great company).
The polyurethane finishes are much safer than nitrocellulose lacquers, but can still take a good while to finish flashing off and curing which may make for objectionable odors for a week or do after spraying indoors and require some ongoing ventilation depending upon sensitivity and how much surface area is sprayed at a time. They are still combustible fumes, so very good ventilation is very important if spraying much surface area in a given period of time and ventilation may need to persist for some time afterwards. Still not totally safe around family but nowhere near as harmful to health as the nitrocellulose lacquers. However, you would likely need to sand everything back down to a consistent state to get a consistent appearance across your cabinets, but polyurethane does provide the wood an often very pleasant ambering tint that gives the wood added warmth (something you do not get from water-based polyacryllic finishes, which are a much clearer coating). However, the water-based poly finishes are the only truly "safe" finishes in that they have no real health concerns from a fumes or explosion hazard, but they lack the often desirable ambering tint and so may require either a light tint coat (stains likely are not an option at this time unless you can fully sand down to bare wood since any remaining areas of old finish will inhibit even staining) or an initial coat of an amber shellac to recreate that amber tone then apply the water-based poly coats on top of that initial tinting coat.
Notrocellulose's main claim to fame in many respects is how very easily it lays down a nice smooth and even finish because it dries exceedingly rapidly (almost upon contact) unlike other finishes which leaves little time for dust or insects to settle in the finish as well as it's great whetting properties (low viscosity) which help it flow smoothly to form a great gloss finish (a great gloss finish is always a challenge since surface contamination while drying can spoil the mirror smooth finish, especially in high gloss finishes). This means that you will need to practice on scrap (sanded plywood as well as tempered Masonite/hardboard is a great initial practice option, as are old pieces of scrap wood identical in species/type to your actual project when ready to test any applied tints, if needed, for a more accurate sample test) before you tackle your actual project with a poly finish to ensure you have learned its traits and behaviour and to avoid laying it down too heavily so that you avoid runs (going a little light on each pass and adding an extra coat or two to make up that thickness later is much better than going too heavy as runs are
a lot of work to repair after the fact). It will also give you a chance to get your spray gun dialed in optimally and gain some added confidence. Fortunately, the oil and water-based poly finishes are extremely durable finishes once layed down properly and allowed time to cure and harden over several weeks. A good solid four to five coat finish should hold up
very well (provided your coats are not too thin, otherwise you will want several more) in even the heavy abuse areas for
many years to come. If you really want to know how tough the poly finishes are, just try to remove a 4-5 coat finish after you have given it a few weeks to harden, it takes an amazing amount of very aggressive sanding to remove the poly from the wood, and even then there will still be poly that was absorbed into the wood further toughening the outer surface of the wood against abrasion. But there is a downside to poly finishes if your coats get too thick (or many in number) and that is that beyond a certain point the wood will begin to take on an increasingly plastic appearance from certain lighting angles, especially with gloss finishes, as plastic is essentially what poly really is. But it really does make for one very tough finish that is well worth learning to spray and finish with, especially for high wear type projects that will see a lot of use and abuse for years to come.
Whatever you ultimately do, I really do wish you all the best and hate to be the bearer of bad news but please be safe as well. With any luck some of our resident finishing experts will chime in soon to expand upon the discussion or add further advice or corrections based upon their own experiences (nitrocellulose is a finish that I have read up on a reasonable bit but never used as I use mostly oil and water based poly finishes along with stains and shellac). We should also have a few luthiers with a good deal more experience working with nitrocellulose lacquers as well who may add further insights.