just go into 'manage images' .. select any pictures you want to watermark and click the 'watermarking' button. it takes you to a photo edit screen. by default, it watermarks your ebay name. but you can change the text, the color, and the transparency to however you like it. now noone can steal your pics!
and for minimun/best offer.. if you're selling your item as 'fixed price' w/ a BIN, after you check the box at the top of the listing page that says 'fixed price', the 'start price' box is shaded so you can't fill it in, then you pick your fixed BIN price, and another box appears that says 'best offer'.. so i think you just check that, and your auction will have your BIN price but will have the best offer added below it.
and real-time payment tracking..
under your 'sales' tab, you can view all, paid, or unpaid transactions. previously, an auction only came up as 'paid' if the customer checked out via auctiva checkout. now, after clicking the 'enable real-time payment tracking' link on that transaction page, it will update all your ebay auctions to show paid or not, regardless of whether or not you use auctiva checkout.
sorry, i haven't done any 'bulk' anything, that's the extent of my knowledge! (and that doesn't mean i'm not wrong about something!
lol hope that helps!