Datapack for day one of SMP

bolded text is what i need help on, the rest is just context.
just dumping my concept idea; if you guys have any ideas for this or for how to do this please lmk - it’s my second datapack i’ve made :)
i’m mostly using this to get it on paper and find any flaws
the concept is for a datapack that is only active on day one of my smp to keep people together! ..in the most chaotic way possible.
the whole thing would only start when someone dies (which i know how to do) that way there can be some buildup and stuff
once someone dies it starts slowly shrinking the border from 25 to 11 across 300 seconds. again, know how to do.
about 15 seconds in to the shrinking it will say, “Your Leader is [@r]” as a title (or something similar). that same person should at that exact time be every tick executing at them worldborder center ~ ~. will that lag the server? should it be on a timer instead, and how often should it be? I don’t know how to do the whole random person thing so if anyone can help with that that would be appreciated
every five minutes the random person should change and display the title again, and when people join the server they should be teleported to said random player so they don’t die to the border. after the original five minutes the world border should start increasing. it should do worldborder add 240 28800. every 5 minutes until the datapack is removed, the world border should center a different person and display that same title. there will also be a function that i manually run that says something along the lines of the datapack is getting removed in x time, get near 0 0 and another function that just says server is restarting to get rid of the datapack.
thoughts, suggestions, opinions, and advice?
fyi this is a private peaceful smp with proximity voice chat. the fact that this is a thing will be a surprise until release day, and i have no deadline to get this done.