Trial player with some questions regarding purchase, sub options, etc.

[Niwashi]

I'm currently on trial, leveling a character with the plan of buying the ARR/Heavensward pack once I hit the level limit

Depending on how fast you're going through the game, another thing you might want to consider at this point is just buying ARR when you reach the limit of the free trial (or get annoyed by the free trial's other limitations), and then buy Stormblood when it comes out. Buying Stormblood will give you Heavensward for free. It's another month and a half until that will be available, but there's a lot of ARR content to get through before you get to Heavensward anyway (unless you want to play as an Au Ra. The new race is the only thing that came with HW that's available to players before finishing ARR).

b. Can we only set up a recurring sub, or is there an option to buy 30 days at a time without worrying about automatic renewals and such?

If you pay by credit card, it will automatically set itself to auto renew. There's a couple ways around that. You can buy Game Time Cards or you can pay using Crysta, a sort of in-house virtual currency SE uses.

Although Crysta payments can auto-renew, they'll only do so if you have enough Crysta in your account, and purchasing Crysta is a non-renewing manual purchase. So just buy enough Crysta for one month (or six months or whatever you want), and then set your FFXIV account to be payed out of that Crysta balance. Your subscription will end when a payment is due that you haven't purchased the Crysta for.

That's how I pay for the game, with Crysta. Each time the sub runs out, I need to go back into the Mog Station and buy enough Crysta to renew it. That lets me keep on top of when money is coming out of my credit card balance.

c. So this game has 2 types of subs, Standard and Entry. My question is, what do the 30 free days count as? That is, will I be able to make more than one character per realm, or will I have to wait until my free month is finished to renew as a Standard sub to do so?

The initial 30 days are a Standard subscription. (So is any time purchased with Game Time Cards, I believe.)