Here is the advice I can give you and what I would start doing asap because you guys are new. You are putting your FC at risk by doing this, even if you think you aren't, and that's why people don't generally do it in XIV. So preparation is going to be your best friend.
You have 2 weeks before 6.4 releases or so.
#1 You dont need 8/8 to get started, while you recruit, the first thing you want to do is secure commitment and instill confidence while detecting issues before they blow up into drama. As such the first step is to get your party to unlock SSS and go to Thavnair X29Y17
There you will ask everyone to finish the dummy for Rubicante EX, this a very low DPS check, far easier than you would encounter even in P5S. It is also a standing dummy so there are no mechanics to be worried about.
If they are having trouble you will point them to https://www.thebalanceffxiv.com/ and research their job rotations. I use the discord, but the website seems to look nice as well.
#2 You will go to Aether and go clear Rubicante with them, set up a pug 6/8 or whoever didn't drop off after step 1 and attempt to clear it. Why Aether? I hate to say it but PFs are dead right now in other DCs and this is just sure fire way to get people without sitting for hours in PF. Any character can DC hop anyways.
Here is a good guide:
https://www.youtube.com/watch?v=1_v6...HectorLectures
#3 AFTER you clear Rubicante, make sure everyone seems excited and up for this type of stuff and tell them in their free time or organize one of your raid nights before 6.4 to clear or at least practice the P8S Dummy in SSS, the place mentioned in #1. This is much tighter DPS but with ilvl 625 + Gear it should be feasible. This is the type of challenge you are signing up for anyways.
If you succeed at all these three things you will be in good shape. And most of these except the EX night is something everyone can work on their time. If you fail at any besides the last one those are major red flags and you saved yourself 4 months and possibly an FC. Hopefully by then you have the 8/8 group but I've seen 5/8 and 6/8 groups pugging the tier no problem. So a full static is good, but not absolutely required. Get ready to lose raid night time filling in PF though.
Or you could just wing it. Anyways, I believe in these methods to prepare you for sucess. GL.