Unlocking Characters

Unlockable characters that I've seen are Alisa, Leo, Steve and
Bryan and the ONLY way to unlock them currently is via
accumulating Gift Points
Heihachi, Jinpachi and Ogre are currently only in the game as CPU
opponents in Arcade Mode but considering their data is already "in
the game" they MAY be unlockable but I haven't seen anything
confirming this personally.
Speculated Characters Winning Arcade Mode shows some splash
art of characters that are currently unplayable, but just maybe it
means they'll be in the game later?
Hwoarang, Jun, Anna, Nina, Devil Jin, Jin, Eddy, Lei, Feng, Ling,
Panda(Kuma?)

Accumulating Gift Points:

You earn Gift Points via Arcade, Ranked and Player Matches for
Arcade and Ranked win or lose you get the same amount but
Player Match seems to vary, maybe based off of level(?)
Logging in: 100 Points
10th Login 100 Points
Arcade Mode: 10 Points Per Stage 30 For Final Stage
Player Matches 10~100 Points Per Match
I got 50 for losing but 10 points for winning two matches in a row
against low level opponents.
Ranked Matches 100 Points Per Match

Gift Point Unlock Benchmarks:

Properly "documented" Gift Point Unlocks that I've been able to
confirm via stream and personally are:
1,000(?) Gift Points: 1st Character (Alisa/Leo/Steve/Bryan)
7,000 Gift Points: 2nd Character (out of the remaining 3)
10,000 Gift Points: 100,000G Reward
30,000 Gift Points: 100,000G Reward AND Third Character
40,000 Gift Points: 100,000G Reward
50,000 Gift Points: 100,000G Reward
60,000 Gift Points: 100,000G Reward AND Fourth/Final(?) Character
70,000 Gift Points: 100,000G Reward
80,000 Gift Points: 100,000G Reward
The next unlock might be at 100,000 at this rate (assuming that
you can unlock the boss characters after the first 4 are all unlocked
that is.)

Earning Premium Tickets
Ways to earn Premium Ticket(s) that I've noticed are also as
follows:

x1 Ticket
Daily Login Bonus (once per day)
Beat Arcade Mode Once
Beat Arcade Mode 10 Times
Beat Arcade Mode 30 Times
Beat Arcade Mode 50 Times
Win 5 Matches (Total)
Win 10 Matches (Total)
Win 30 Matches (Total)
Win 50 Matches (Total)
Win 100 Matches (Total)
Win 200 Matches (Total)
Win 300 Matches (Total)
Win a match while using ONLY a Premium Ticket or Coin (refunds
your used currency)
(Some values in-between 100 and 300 are missing)
x3 Ticket
Login 10 times

Premium Tickets

Premium Tickets allow you to keep playing as long as you
continue to win it will return your ticket to you. If you lose when
using the Ticket you get 500 EXP instead the smaller amount. Also
you can use Premium Tickets in Arcade Mode but from what I've
seen it only gives you a x3 Multiplier to all of your bonuses (not
counting the current x2 bonus that is active right now)

Premium Coins

Premium Coins work exactly the same as Premium Tickets they can
only be consumed when you have run out of the Token you are
attempting to use Arcade or Online. When you win a match you are
"refunded" one Token in the form of Premium Ticket to continue
playing similar to an Arcade Machine. If you lose you have the
option to use another coin or buy more.
The coins can be purchased from the PSN store in bundles of 4, 10
or 30.
4 Coins $.99 (~$.25 each)
10 Coins $1.99 (~$.20 each)
30 Coins $4.99 (~$.17 each)
Winning with regular tokens doesn't win you back anything unless
you reach one of the benchmarks.

Regular Tokens

Regular coins refresh at a SAME rate if the system is OFF or ON
Arcade Coins: Max 2 Refreshes Every Hour
Online Coins: Max 5 Refreshes Every 30mn
Regular Tokens are used BEFORE Premium Tickets AND Coins.
If you use an Arcade Coin and lose you do not get to continue from
where you left off.
If you use an Online Coin WIN OR LOSE you gain the same amount
of points. (But because you gain tickets for accumulated wins you
lose out on getting potential tickets)

Leveling Up

You gain EXP Points from playing matches, and use Skill Points
and Fight Money to level up your characters three stats Power,
Endurance and Vigor. The Skill Points you gain are given to all of
your characters when you level up.

Experience Points

EXP works slightly different than Gift Points, you gain different
amounts if you win or lose but it depends on what you're using.
Gaining EXP

Arcade Mode:

With a Regular Tokens: 10 EXP PTs Win/Lose
Final Boss Fight gives 30EXP Win/Lose

Online Matches:

With a Regular Tokens: 200 EXP PTs Win/Lose
With a Premium Ticket/Coin: 200~250 EXP Win 500 Lose
EXP gain may be based off of ranks, where higher ranks gain more
EXP from a match.
Using Skill Points
ALL characters gain 4 Skill Points when you level up.
If you unlock a character after levelling up they will have access to
all of the Skill Points you've obtained relevant to your level. You
can use them to upgrade one of the three attributes, each level
requires a set amount of money.

Fight Money Cost Per Point:

1-4 2,00G 69-89 110,000G
5-9 10,000G 89-109 120,000G
9-19 20,000G 109-129 130,000G
19-29 30,000G 129-149 140,000
39-49 50,000G 149- ? 150,000
49-69 100,000G