How humanly survivable is my world?

Please note that I have had some incredibly helpful and useful suggestions here that I have decided to make some major revisions as a result. I will reduce the overall atmospheric pressure and partial pressure of oxygen figures but will thus need to rethink my flying predators. I think that will go a long way to reducing the humidity levels to make them more tolerable to my crew. I want them uncomfortable, but not dead (apart from those attacked). Once I have rejigged things, I will come back here and correct. Thank you to all who have helped!

This will be my first post here.

For my novel-in-progress, I have a "hot 'n heavy" Earthlike world my crew are exploring.

I need to know whether the humans amongst my crew could breathe and generally survive medium-term (for say, up to 9 or 10 Earth months) and long-term (indefinitely) on this planet without technological support.

Genetic enhancements are available but not all crew have them.

Please assume all crew are extremely fit, that high standards of physical fitness are part of their job description. Assume also they do routinely use drugs to help manage hyperoxia and thermoregulation. They have also acclimatised as much as is humanly possible to the environmental conditions before leaving their landing craft.

If there are any issues, I will finagle technological solutions to them, but I need to know what medical issues my crew may face if I am to know what needs finagling.

The crew will need to be active if they are to evade my alien megapredators (some of them big and scary, but nothing too intelligent, the brightest would make a T. rex look like a Mensa candidate), so there will be some running, jumping, screaming, squelching and dying (not necessarily in that order).

This is the 2nd planet orbiting the primary sun of a binary system.

The primary sun is a K0V orange dwarf main sequence star appearing a fraction smaller in the sky than does our Sun when seen from Earth, but 3.18% brighter due to less distance (mean distance to planetary primary = 164 million km).

The secondary sun is a K1V orange dwarf main sequence star appearing in night skies (at the time of arrival in the local planetary year) as a "star" of apparent magnitude -17.5 (104 times brighter than a full Moon on Earth).

A small moon orbits so closely to the planet it is tidally locked and has a planetosynchronous orbit. This moon is 582 km in diameter and orbits in lock-step with the planetary rotation of a little over 31 hours. It is a red moon seen low on the horizon as they are exploring the cooler polar region, leaving equatorial areas to robots.

Both suns possess a small complement of planets.

Planet being explored: Mean equatorial diameter: 13,008 km

Orbital period: 219.93 Earth days / 168.86 Local days

Rotational period: 31h 15m 34s

Mean surface gravity: 11.30 m/s^2 (1.15G)

Atmospheric pressure: 274.6 kPa (2.7 Earth atmospheres -- I need this to help some of my local fauna fly) (UNDER REVISION, AS ARE THE MEANS BY WHICH MY ANIMALS WILL FLY)

Atmospheric composition: 74.1% N2, 24.7% O2, 0.5% H2O, 0.7% other (assume nothing toxic) (H2O AND O2 FIGURES UNDER REVISION)

Approx mean midday planetary temperature: 74°C / 347K / 165°F

Minimum nightly temperature at the landing party encampment (north polar circle late Autumn/Fall): 30°C/303K/86°F

Maximum midday temperature at the landing party encampment (north polar circle late Autumn/Fall): 46°C / 319K / 115°F

Local water supplies are plentiful and they have the tech to synthesise their own even if there are no local supplies. Essentially there are no limits to their supply.

Local plants and animals are toxic to eat due to incompatible protein chemistry. Zinc-based haemoproteins are the norm for animals on this planet. Crew have brought their own rations, but can synthesise foods using gravitic technology.

Any assistance with this would be greatly appreciated.