With the talismans, like-for-like talismans (i.e. same slot, number of pips, etc) will have the same stats, and you can adjust your anima allocation (from level 20+) to change your stats to best fit the role you’re doing. Glyphs will have an impact too on how your build works. Generally for healing, you’ll want critical and crit power ones, with one or two hit rating glyphs if you’re using AR.
You can buy blue/purple gear right away, but if you start out with them, you’ll be hugely overpowered, and it won’t be very challenging. Also, I know you need to be level 50 to fuse items to make purple (epic) gear, you may need to be a higher level to use it.
For abilities, there are some good healing ones in both. I currently run Blood/Fist as healer, but for most of my levelling, I did AR/Blood so I’ve experience of both. The two I found most useful for Assault Rifle in endgame content were…
Unveil Essence - really good for group stuff, as it not only has an instant group heal, but also lets people leech for a few seconds afterwards. There’s a passive that increases the healing too.
Essence Grenades - again, great for a group because anyone standing in the blast zone gets a nice big ol’ heal! I seem to recall that the healing on this one (which also deals damage) was around the same, if not more, compared to the Anima canister grenades. The Explosive Expert passive is really useful for this, too.
Anima Suffusion I have heard is a popular one for healers as it renders your defensive target invincible for a time. I’ve never used it though!
For fist, the Regeneration elite ability is pretty awesome. Massive group healing (especially with the passive) and cleanses too. If fist is your offhand, you might also want to add the “Wild nature” passive, which constantly builds fury while in combat. Without it, it can take several bosses through a dungeon before you build up enough to use Invigorating Wrath (which takes up an ability slot).
That said, I haven’t bothered with IW for a while. The only fist ability I use in group content is ‘savagery’ to boost someone’s attack rating for 6 seconds in combat, though I do now have Manticore Wrath Inducers, which automatically go into invigoratign wrath when the fury meter is full. But the trade off for not having an ability slot taken up by IW is that you have much less control over when to use it.
You might also find the how to heal guide useful- https://www.reddit.com/r/SecretWorldLegends/comments/6p403r/guide_how_to_heal/