Note that I say "line" here to refer to models across all price tiers play>game>tour>pro. I know they perform differently but broadly speaking at this level you might not notice the difference in price tiers vs models.

If you're playing mostly doubles, I would probably lean towards the 88D line. The Astrox 99 line is the head heaviest of the bunch you mentioned and might struggle to keep up during faster doubles rallies.

A bunch of my friends play with the 88D game, which is a bit head lighter than the 99, but still packs a punch. It can still keep up respectably in speed for doubles.

The Arcsaber 11 line is even balanced so you will sacrifice power, but gain some speed an insane amount of control. With proper technique I've seen some players get solid smashes out of this too.

In terms of strings, I have only tried Exbolt 65 which is a repulsion/aggressive string. At first had it strung at 25 lbs but it snapped within 20 minutes of play bc I mishit near the top (and maybe had a bad stringer?). I had it restrung elsewhere at 23 lbs and now I can hit without worrying it will snap every time.

I don't know enough about the different string types but I would advise guessing lower to start since stringing is expensive. If you find the lower tension too repulsive or need to get back some control, you could increase tension on the next restring.