(1) For a small ship and being close to nature, our cruise met our wishes very well. The decks are close to water level, and the captain keeps the ship as close as practical to the wildlife and hangs around for plenty of time.
Before the cruise we did a Road Scholar program in Denali and the Kenai peninsula. On it, we met two couples about our age (late 60s+) who had just done a Lindblad/National Geographic cruise. Those boats have zodiacs onboard and get into the water a lot, so they might get even closer to critters. These folks, however, said that they were really wrung out by the end, and of course the cost is much higher.
(2) We were not able to find the smaller ships on the discount sites, but it is a good idea to ask the cruise lines themselves about discounts or cabin upgrades.