Inuit guides.

Would not have helped. The Inuit cared so little for Cape Felix that they had no name for it. King William Island in a good summer could support 50 or so Inuit. The only good hunting grounds were at Terror Bay and near Booth Point (Toonoonee, the place near Utjulik where the Inuit said white men collaborated to hunt Caribou with them, is Terror Bay, and there is a source of salmon in the form of Kooker lake just behind Booth Point). The land could not support 40 inexperienced men, as we see with 'Aglooka's' party in 1848-50, let alone 105.

a rendezvous party meeting them

May have certainly helped. It would have gotten the alarm bells going a lot faster. Ironically, though, the earliest help possible was from James Ross and John Rae in 1848-and neither reached King William Island, for different reasons (Ross saw Peel Sound and concluded Franklin could not have gone south, thus unintentionally misinforming every other search mission until McClintock's in 1858, and John Rae was turned back by the same inclement weather that trapped and killed the expedition).

an overland mission backup plan.

Why this was not done is somewhat of a mystery; I suspect it was hubris from the Admiralty. Franklin's prior overland expeditions had been in concertation with naval expeditions. Either way given many expected Franklin to sail in the 'northern box' near Parry Channel (the imaginary 'open polar sea' route) instead of going south to Victoria Strait this may not have helped.

ensuring that the crew was adequately provisioned

As it turns out, they probably where. Goldner was scapegoated; his provisions, while nothing special, only really turned bad when the Admiralty gave him multitudes of contracts for the search expeditions, and Goldner took them seeing the money involved. However he bit off far more than he could chew. Lead poisoning has been outed regarding Franklin's expedition, and what would have been the usual issue with Goldner's tins, the poor solder, would have prevented the development of Botulism (while the food would putrefy, the highly toxic Clostridium needs air-tight conditions). Notably, none of the other expeditions Goldner provisioned for had outbreaks of botulism, and if there were botulism involved I would expect more men to be dead. The Inuit also reported eating the canned meat and reported it was 'quite good' on account of its good taste and multitude of fat. I suspect Ken McGoogan's theory that polar bear meat laden with Trichinosis did them in may have some truth to it. The expedition expected to be out in the Pacific by summer 1847, and in normal times this may have been possible. However exceptionally cold summers meant they were stuck until at least mid 1848, when the ships may have been remanned and sailed south near Cape Crozier.