Update Maizey 6/23/22
Maizey has been here for a month... it feels like she's been here for her whole life, but only for a minute, at the same time. I adore her, and so does Hubby. One of my cats (Achmed) loves her... we're working on the other 2 (they're getting bolder, day by day).
Her first (and only) heat started 6/14/22... she's doing well, but this limits us to only working here at home, and taking rides in the car. I don't want to risk pregnancy, or upsetting other dogs unduly, so to be safe we're limiting exposure. She's scheduled now to be spayed on 7/14, but the recommendation is to wait for 12 weeks after the heat before spaying, so that her body has time to reduce the blood flow to the uterus/ovaries. Spaying too soon can lead to excessive bleeding issues during the surgery. We'll discuss this at the next vet appointment for her booster shots next week, and we'll be able to resume training in public areas when she's finished with her heat (around July 7).
How has this heat cycle affected her behavior? At this point, not at all, because she's been segregated from other dogs here at home. I'm not risking a male attempting her (and possibly getting rebuffed -- or worse -- accepted!), and I'm not risking inter-bitch aggression due to hormones. It's not necessary... we have plenty of time to work on training.
Maizey's clinginess has been mitigated by her training to the point where I would term her 'clinginess' as much more typical of St. Bernard behavior... as I type this, she is lying on the floor in another room, chewing on a chewy. She now stops outside the bathroom door if it's closed, and whimpers until you answer her, then lays down. When she goes outside to pee, she'll check the perimeter of the yard, not just peeing on the first available spot and hurrying back, as she did before. She's starting to understand the differences in the way I dress... jeans means that there's a good chance we're going somewhere that she can go... scrubs means that I'm going by myself (to work), so she lays down and chews a chewy (once a dog learns that certain behaviors predict going for a walk, or going in the car, it's really useful to have them understand the OPPOSITE) . Many of my dogs have learned this, based on their history.
Maizey has become very vocal, demanding what she wants in a series of growly-grumbly-yodels. She is especially vocal with Hubby when he comes home, and he's learning to give her attention to turn it off. <g>