Multiple behavior issues

I think my poor Gidget is unhappy.  She's my two year old long-hair "princess".  She's my baby.  She's also developing some behavior issues.

First, she doesn't like our two kittens.  They are nine months old and have been integrated with our three cats (including Gidget) for the past five months.  I admit that Casper is annoying and plays a little too rough, but Gidget usually just hisses and runs away when he does this.  Now she hisses and runs away from both kittens all the time.    When she lays on the floor while I brush her, she will get up and run away if either of the kittens come within 10 feet.  She even tried to run away when she saw Casper's tail under the closed door.  She constantly hisses at them when she walks by them.  However, in the past couple of days she has started "stalking" Abby, who is half Gidget's size, and swatting at her.  All of this, despite having 4 Feliway plug-ins spread throughout the house.

Second, today she got up on the kitchen counter (a naughty little trick Casper showed our cats), squatted over one of the kitchen towels and peed on it.  My husband gave her a "Gidget, no!" but not yelling or anything, removed her from the counter and cleaned up the mess.  I'm calling the vet as soon as they open to make sure she doesn't have a UTI, crystals, etc.  We have four large boxes for five cats/kittens (all our home can hold until we finish a few more renovations).  We use unscented clumping litter, scoop twice a day, and clean each box thoroughly once a month.

Now I'm wondering if she's just feeling lonely for human companionship (if everything checks out okay physically with her).  I worked 5 night in a row before Thanksgiving (so I could take time off to visit my sick father), and my husband worked his normal 7 nights in a row.  Although I tried I didn't get to spend much "mommy-Gidgey time with her during that week.  Then my husband and I went out of town (the second time since we've had our cats) for four days.  We had the cats separated from the kittens (feeding issues), and we had a pet sitter come in twice a day to feed the cats/kittens and scoop boxes.  Once we got home, it was back to working mulitple nights in a row and not having much time to spend with the cats. 

Could this increase in meanness to the kittens and inappropriate peeing be due to stress from not spending enough time with Gidget these past few weeks?

Could a calming collar possibly help her (along with spending more one-on-one time with her)?

One of our older cats was doing the same. Went do far as attacking my baby and attacking our fragile rescue kitten. Out got so bad that even her buddy Zeppelin would run her off and disliked her. She would pee on things worse than normal. We tried separating three babies from her and constantly cleaning the litterbox, but even as my baby got older she wouldn't stop attacking her. A finally came to the conclusion that she wouldn't ever accept the others. She was really just a one cat family kind of cat. A found her a new home with a couple where she could be queen again. She's been doing much better. He new owners say she hasn't been having any accidents and is her friendly self once more. Nothing was wrong medically with her. I have learned that cats are born with this instinct that kittens are bad. Bad and dangerous because their mother is usually nearby and will attack any unfamiliar cat near her babies. I hope Gidget can learn to accept them. I wish I had better advice to give you.