I'm remembering a professor of mine one time saying that answers were relatively easy to come by, but that asking the right questions was more difficult.
Observation He was right!!

Firstly, I ordered Origa 1.2 and am now more aware of the lacking DVD capabilities. My BIG question concerning the DVD capabilities is if this is strictly for playing back up DVD's or if it also pertains to Original and Original Import DVD games?
ANWSER: I believe that with Origa 1.2 DVD original import games on SCPH 30000 will work with a DVD Region X swap (which is very simple indeed). There is no report yet of OrigaChip v1.2 having been installed on the 35000. The problem you'll have is that if it can't boot original imports without a swap, then you'll need the Japanese DVD Region X (avaialble in the UK from Madeira Games). The OrigaChip is not about playing DVD movies. DVD Region X will handle this and it won't play PAL movies on the JAP PS2; nothing will.

Secondly, if it can't play original import DVD games is there a way I can add another chip or would it just be better to order the new 1.25 that doesn't have this problem?
ANWSER: I would order the 1.25 but if they can't supply then possibly take a chance with the 1.2. I advise caution because you'll want to satisfy yourself that the chip will work with the 35000.

Thirdly, (this is for my peace of mind) I've got this PS2 350000 Japanese model with serial code J64XXX... and the Origa people told me the chip would work alright, and I'm guessing it's a V5 board; but I'm a bit worried that somehow this is going to turn out to be a really new PS2 model that no one has dealt with before. I doubt this is the case it's just that everything I read says, works on model 30000X instead of 3XXXX (which would make me more comfortable).
ANWSER: That's my worry too. Make the Origa advice a condition of your order is all I can suggest. For once, I'm lucky to have an old item - the 15000!