1B options are pretty uninspiring - Moose Reunion? (102 wRC+), Carlos Santana (98 wRC+), CJ Cron (92 wRC+, day to day due to his back), Dom Smith (91 wRC+).
Even though he hasn’t played a ton of 1B (87 innings this year, 97 innings in 2019, 537 innings in 2015) I’d be fine rolling the dice on Canha over the above names.
Getting one of Tommy Pham (129 wRC+, but day to day with a groin), Randal Grichuk (117 wRC+) or even Teoscar Hernandez (96 wRC+ but StatCast says there’s a lot of bad luck in there) for DH would be my first focus though.
Don’t think Ohtani gets dealt, but if he does and it’s to TOR they have Vlad Jr and Brandon Belt (125 wRC+) at first/DH currently. Could swoop up Belt in that scenario.
If LAA sells, Brandon Drury (122 wRC+) would be another good option, though it looks like he is currently rehabbing a shoulder.