Possibly yes and possibly no.

AmEx personal card cannot be upgraded to biz card. Can apply for a biz card, even if only a notional biz, as “sole proprietor” using SSN, tons of discussion all over blogs and discussion boards in that regard.

I believe there’s only 1 AmEx travel portal and upon booking a qualifying airline ticket (generally biz or 1st on any airline or economy on selected airline) if one selects “pay with points” and one has a biz plat account, the 35% points back (rebate) will post to MR balance about 3 days later.