Post-Cycle Stocking / Medication

My mind is on my 75 gallon today and I was thinking about how I am going to stock after cycling. I will be doing a fishless cycle with 4ppm of ammonia running a single SunSun hw-303B that, other than the sponges it comes with, will be filled with biological media. I will be adding a second SunSun hw-303B 2-3 months after I am fully stocked. My stock list is as follows -

7 (2") Fancy Goldfish
5 (1") Purple Mystery Snails
5 (3") Longfin Albino Bristlenose Pleco


Now, as much as I want my snails first, I think I am going to do a prazi treatment on the goldfish once I have all seven. I may get my snails and put them in my empty 10 gallon just so I can be appeased that I have them, lol. I read mixed reports on whether or not prazi will harm them and I just don't want to take the chance. I will add them a month after the prazi treatment is finished so the tank should be cleared out of all medication.

I will be adding the goldfish about 2-3 at a time every 1-2 weeks. I know I could fully stock immediately with dosing 4ppm but at $5-7 a piece, I just won't be able to afford all the goldies at once. I will then add the snails while I search for the bristlenose locally.

Now, for the questions -

• Will it hurt anything to have set my tank up to handle 4ppm of ammonia and then not add the fish all at once or will it just cause some BB die-off and I'll have to stock slower?
• Should I float the snails in a plastic breeder box for a week or so before adding them to the tank or will they do okay introduced immediately?
• Is it safe to add all five snails at once or will they need to be added a few at a time?
• Will it be safe to add all five baby bristlenose at once or, again, a few at a time?