Salthorae
Imperial Mountain Dew Taster
Also, I should emphasize that Extra Attack is worth a lot as a grappler/tank.
When you wild shape as a Bear you gain the Bear's Multiattack Action, which is redundant with Extra Attack isn't it? You get that with wild shape at level 2.
Extra Attack from Bladesinger only matters when you're not in Bear form.
If you dropped all your bladesinger levels for Druid, you could also at those levels be using Wild Shape to turn into an Earth Elemental starting at Druid 10.
With the Bracers of Armor, you've got 19 AC, a possibility to rage, but your attacks are +8 & 2d8+5 vs. +6 & 1d8+4 for a Brown Bear or +7 & 1d8+5 for a Polar/Cave bear, not to mention 126 hp as an Elemental with damage resistances and immunities vs. 34 hp for Brown Bear and 42 hp for Cave/Polar. Also, Elementals still have the multiattack feature.
If you take Tavern Brawler if you hit with any attack you can initiate a grapple as a bonus action as well. So that will play more into your grappler concept than whatever forms you choose.