If I want my Geralt with his particular character histories do I need to play the first two games again? I no longer have the original save files. Or have they removed the level of history detailed one would gather from having played previous games (like in the second game where people react differently based on very specific interactions had during the first game)?

Witcher 3 is, for all intents and purposes, an entirely standalone game and your decisions from the previous ones have only extremely minor effects, almost negligible. Additionally, during W3 playtrough without imported saves, you will be asked series of questions about your past decisions when it comes to those which do make said minor difference. Long story short: No, there really isn't much of a point in importing your existing Geralt.

It's helpful if you remember the story of previous two games, but even then, W3 is much more of a continuation of the story told in books than that told in previous games, so my only advice would be to go and read those if you've not done so already.

So absolutely no character sequences dependent on how you treated thaler or vincent or shani or the blonde bob headed chick or any of that stuff?

Well let's just say that there's a character which just gets revived even if he died in W1. I think that pretty much attests to how much did CDP respect your decisions from previous games. Your decisions from W1 are all ignored completely and decisions from W2 are mostly just mentioned as a line or two in a dialogue and then promptly forgotten about. There's one, single decision from W2 which will may add a quest and a character - if you want to know which one it is, I'll tell you a spoiler so that you know which option to pick in the dialogue where you get to choose your W2 decisions. And that's it.

plrase do so. I have played #2. Are ypu talking about Sile?

***** SPOILER (for others) *****
.
.
.
.
.
.
.
.
.
.
.
No, it's Letho of Gulet.

Will decisions from witcher 1 even effect what decisions you can make in 2, and thereby indirectly effect witcher 3? (It uas been a long time... I really hated #1).

No and no.