First off, yes... "pagan" is a really big umbrella term that covers many many different paths. And just like the "christian" umbrella covers groups that are radically different in their particulars and traditions, different pagan groups ceelebrate holiday in different ways and for different reasons. There's the whole joke about asking ten pagans and getting 20 answers!
For your next question about "real" traditions... I think you may be hitting up against what I call the Holiday vs Holy Day divide. For example, the religious meaning and celebration of Christmas (a Holy Day) differs from the secular or family traditions that surround Christmas (the Holiday) even though both are happening at the same time. So it can be confusing to tease apart what is "holy day" and what is "holiday". Which is what I think you might be asking? How close are the "holiday" traditions of Halloween to the "holy day" traditions that surround the period of time at the end of October/beginning of November (often but not always called Samhain by those pagan umbrella folk)?
While I think the answer to that depends on the specific pagan religion (remembering that pagan groups vary as much as christian groups do, if not more
), I can describe our Samhain Holy Day beliefs/traditions.
We're Druids (ADF style) with a Norse hearth culture. That means we celebrate Samhain as a type of harvest festival. While there is a "vegetable/grain" harvest a bit earlier in the year, the end of October tends more to a "meat" harvest. In an agricultural society a decision needed to be made about how many of the livestock could be fed through the winter... diviners and elders would read the signs and hope they'd judged the season correctly (hence the emphasis on divination at this time of year), then tell the community "Long winter ahead, butcher more livestock" or "short winter, keep the livestock". If they got this wrong there could be serious fall out... butcher too many and then have a short winter and you've wasted your resources/limited the amount you can achieve in the next year BUT get hit with a longer winter than expected and your livestock will starve and that's a much bigger deal.
One way or the other, food would be plentiful, butchering and conserving meat and supplies would be well under way, the focus would be on the family and the community while at the same time there would be a very visible reminder of life/death. I don't know if you live in hunting country, but around here the hunters will be putting up deer on their porches soon... which makes for a pretty obvious reminder of the whole "circle of life". Anyway, this all lends itself to a focus on family past and present and future, a realization of life in death and death in life, a bountiful harvest table with the knowledge of lean times to come. Sort of a balanced, see-saw, season of thanksgiving.
And in our religion (again, ADF style druidry with a focus on Irish and Norse history/culture) the focus on family past and present plays out in various ways... we make an altar and decorate it with reminders of family and friends who have died. We make a meal with favorite foods that remind us of those loved ones and leave a little of the food from that meal outside on our offering table. We also leave out gifts for our unknown ancestors, for the spirits that will accompany us through the year (for example, the spirit of Deer and Turkey and Pig that will be butchered so that we will have food during the winter), and for the gods. We meditate and contemplate and read omens that give us an idea of where the coming year will take us... pesonally I draw a few tarot cards, remember my family and friends who have passed on, put in our order for the meat CSA, and remind my kiddos that it is no longer safe to wander the woods around our home (even in blaze orange).
In terms of the secular holiday aspect... we go trick or treating, we carve pumpkins, we toast pumpkin seeds and eat more chocolate in one night than we do the rest of the year combined.
We go to the "pumpkin party" at my dd1's waldorf school and sing songs about silly witches flying over ditches.
I've probably rambled right past your original questions but... Yes, Samhain is a religious holy day in many pagan traditions. It's purpose and meaning vary but are generally related to harvest, the new year, family past and present, death/rebirth, and divination. In modern American culture there are secular holiday traditions that mirror or grow from these holy day traditions. And...ummmm... I talk too much!