You can replace the ammonium sulfite with an equal weight of sodium sulfite, but you cannot replace the ammonium bromide with sodium bromide or it will be VERY slow to bleach. For the purists the ratio of the molecular weights of ammonium to sodium are virtually unimportant for these purposes.
You can use EDTA acid and neutralize it with ammonia as well rather than use disodium EDTA. There are many ways to do this.
All bleaching in this is based on a mutual reaction of ammonium ion, bromide ion and ferric EDTA (or PDTA). If you put in too much sodium ion, the bleach slows down to a crawl. Keep the sodium ion at a minimum and if you overshoot in pH adjust, going too acid, don't use sodium hydroxide, use ammonium hydroxide to go back up in pH.
You can get ammonium sulfite from the Formulary by special order (I think) or from ANTEC (kyantec.com).
Avoid all potassium ions like the plague in both the bleach and fix.
Film blixes have a great tendancy to cause silver retention with associated higher grain and blocked highlights in the print. They are often less stable than bleach then fix processes. There are blix formulas. I am working on one right now that should solve these problems.