1) Garuda is still the best physical (especially with razed ruin), and because of Atma of the Beyond (30 MAB 30 Ice 30 Light) Shiva is now the best magical (provided they don't resist ice of course)
2) Hastega is pretty nice, especially if there isn't a WHM or RDM in the party. If there is, you can cover haste for them if you want. When I'm on WHM I am willing to haste my entire party. When I'm on summoner, same applies. Really just depends on if your other mage sucks or not, or if they are strained and your haste will help a lot. Earthen Ward and Ecliptic howl are always good, yes. If you're playing more the support role, rotate stuff. If you're playing a more aggressive role vs something with AoE, you can probably spam pclaws and use hastega/whispering wind to help out on healing. As long as you're willing to be versatile, as you seem to be, you will be fine.
3) I'd personally use dream shroud, and then if something you need to nuke, use T2 pacts. If it's something you can physical, throw on some pclaws (with atma). You can use Shiva's favor if you want to, but throwing on a new dream shroud is going to reset it. I personally don't really like just sitting there with favor on for blms, so I do stuff. At 75 before the level increase, I did Ouryu and was in a blmx4 sch smn party. I used Wind Blade, and healing ruby 2 a lot. The scholar erased and I kept the blms from dying. The BLMs did 12, 10, 9, and 8k. Garuda did 6k. I didn't have the BP timing down or she would have done more (maybe ~9k). I surprised everyone and they were talking about my smn on vent, and bringing a smn more often, it was kind of funny. Considering I also kept them healed with Whispering wind/Healing Ruby 2, I thought that was pretty decent damage wise. Essentially, while you can just leave shiva's favor on, I think it's kind of a waste, especially since the higher their MAB gets, the lower a damage increase Shiva's favor is. (MAB+0 -> MAB+10 is a bigger (10%) increase in overall damage than MAB+50 -> MAB+60, a 6.67% increase in overall damage)
4) Healing pacts (ie healing ruby 2 and whispering wind) and most magical damage pacts (ie lunar bay, aero iv, holy mist) use TP. Diabolos' pacts don't (i.e. nether blast, night terror), astral flow pacts don't.
5) I'd say the T1 and SMN skill look good. The merits are personal preference. As I said in 1, Shiva has the highest damage potential now, and ice is one of if not the best element. Wind Blade is nice too since garuda is cheaper usually and more versatile (healing, haste, shadows, damage). Personally I have 5 Wind Blade 5 Heavenly Strike, but with the tp boost on smn legs, regain on caller's pendant, and now mana cede, level 1 bloodpacts are better than they were before.
6) I haven't tested it myself, but the windurst wotg atma is supposedly able to bypass the 45 second cap. I am almost at the -10 bp timer magian staff... though I haven't seen anyone say if that goes beyond the cap or not (since it's affinity). If I find out, I'll post that here...
I hope that helps. Anyone else feel free to elaborate or offer their opinion