Mera Peak is not technically difficult - apart from the altitude. Because of that, you need to use a lot of time to acclimatise. From Lukla, we took 10 days to walk to the Mera's north col at 5500 m, including two days when we stayed in the same camp, but walked up to about 1000 m higher than our camp, then back to it. Even then, many of us had problems with the altitude on the final peak. Of 12 clients and 3 guides, only 8 clients and 2 guides reached the summit. I remember standing at about 6300 m thinking, I can't raise myself another step. But we had a rest and it went - slowly.
It's just a walk to the north col and a technically easy tramp up a snowy crevassed glacier from the north col. You need crampons and axe, and we all used plastic boots. The guiding company (Karakorum Experience) provided ropes, harnesses and belay equipment.
We were there in November, and it was cold, about -20C in the morning when we set off for the final climb, so you'll need a good sleeping bag.
Above about 3500 m on the walk in, we had below freezing in the morning and it got cold very rapidly in the evening after sunset. A good tip is to defer washing - self and clothes - to a break in the middle of the day, when it was much warmer in the sunshine, surrounded by glorious snowy peaks.
After Mera, we continued down eastwards into the upper Arun Valley, then crossed into the Khumbu over the Mingbo La. That was another story - abseiling over 100 m down nearly vertical fluted ice. Some of the clients were sent part way down to help the porters, and we were last down the glacier - a descent of a steep icefall in the dark at the end of a 12 hour day.
But you'll be going out via Lukla, so you'll miss out on that fun!
Have a good trip.