Sharp, the 21-year-old law graduate from Edinburgh, eased into the final of the 800 metres in her first major championships wearing a Team GB vest.
McConnell was third fastest qualifier for the women's 400m showdown, 10 years after she won a bronze in the corresponding event in Munich.
Steph Twell's place at the Games is in doubt, however, after the Scot's last-minute withdrawal from the 5000m while hammer thrower Mark Dry continues to sweat it out with rival Alex Smith for a single slot.
Sharp, whose father Cameron ran in the Helsinki stadium 29 years ago in the first World Championships, finished second in her 800m semi-final to qualify for the final in a time of 2.01.88.
Her fellow Briton, Jemma Simpson, will join Sharp there after a third-place finish that was one of the fastest outside the top two in each semi-final and a fraction quicker than the Scot's run. Sharp duly went through as the fifth fastest of those now in the final.
Sharp's case for an Olympic place is strengthening by the day after Jenny Meadows was forced to pull out of the European Championships. Meadows has A standard runs under her belt, but all are from 2011.
McConnell, meanwhile, will compete for a European Championship medal at the age of 33 as she strives for a third appearance at the Olympic Games. She produced a season's best 51.98 in the semi-final in Finland to post another Olympic B standard. She will run for the third day in a row tonight and is also involved with the GB 4 x 400m relay squad over the weekend.
"That was tough," said McConnell. 'Yesterday felt really good but that was tough. It was a season's best by a few tenths so I have to be happy with that. Being in lane six I had no choice but to do that [go out fast].
McConnell has an A standard from last season and needs to run under 51.55 in the final to post another to bolster her claims for a place in both the individual 400m and relay at London 2012.
Twell missed the Aviva Olympic Trials in Birmingham but had been passed fit for Helsinki following a foot injury. She does have the A standard for the 5000m.
Dry slipped out of the European competition at the qualification stage. The Scot threw 69.32m and 70.27m in Helsinki – about four metres short of his PB – and it wasn't enough to reach the final.
Dry finished 25th out of 30 competitors in his first senior competition for Team GB and with four Olympic B standards to his name, his place at London 2012 now seems certain to come down to what rival Smith throws at a British men's league match over the weekend.
'I am disappointed because it has been a fantastic experience being here at my first major championships,' said Dry. 'It is a little confusing. I feel good and I've been throwing well but it wasn't particularly good out there. I had a foul on the second throw but it wasn't any further than the others so it is all very frustrating.
'Can I make a case for myself for the Olympics? I've had four B standards and five other occasions when I have thrown over 73m so I've shown a lot of consistency. I think Alex and I could be contenders for an Olympic final throwing that distance so it is a shame that only one of us will get taken."
On a rollercoaster day for Scottish interest, James Brewer's withdrawal from the 1500m through illness only added to the frustration for Chris O'Hare. The Scot was controversially left out of the Europeans, with Brewer failing to make it through the heats last weekend in Birmingham as the Scot claimed a bronze medal.
european championships Scots still in frame for Games places