1) I actually meant "spring" as in go ahead and pay extra for the tub heater. I was having trouble finding on the Lowe's website on my phone, so here it and the tub are at home depot https://www.homedepot.com/p/American-Standard-EZ-Install-9-in-x-3-in-1500-Watt-Whirlpool-Heater-EZHEAT-100/204765546
And tub
And the drain that goes with it https://www.homedepot.com/p/American-Standard-American-Standard-Deep-Soak-Drain-1599-500-020/100677630 2) you can have Lowe's install not (or home Depot) but if you can avoid it I would. You need a contractor to take out the old tub and install they new, and the contractor will bring on a plumber and electrician to do their part. Do you have any friends/coworkers who have had work done ask around for recommendations.
3) decals/appliques like this https://www.amazon.com/SlipX-Solutions-Adhesive-Non-Slip-Traction/dp/B00I81O540/ref=zg_bs_85961011_3?_encoding=UTF8&psc=1&refRID=NBE4VH7F5BYFDT4AX6ME