Any recommendations for senior bats in cold weather (mid 40's)???

Buy a small propane heater and keep your bats next to the heater.

Use an ASA or USSSA bat if you have access

Purchase a $30 Walmart bat and swing away. If you decide to use your Senior bat and it cracks, don't expect a manufacturer to replace it. Remember, cold balls will break bats as well.

Can I use my DeMaraini Flipper Aftermath (ASA) bat even though its not stamped for SSUSA nor has the BPF rating (website says its 1.20)

I have a Miken Johnny Bailey and a Dudley Bobby Nifong that both hold up well in cold weather and don't sting my hands. Also liked the 2 pc Louisville Hyper Z for cold weather.
I've hit BP in temps as low as 35 with those. I keep them warm until I'm ready to hit.
Keep in mind that I'm a gap hitter, so if you are regularly clearing the fence, all bets are off.

My POV: Don't swing a senior bat in those temperatures. Instead, look for a "sibling" bat in USSSA (or another sanction...where you can get a warrantee). For example, if your gamer is a Suncoast Senior bat, go for the USSSA Suncoast Ruckus. It swings the same as its "sibling". The USSSA bat also comes with a one year warrantee...so if you crack it...you can get it replaced. Senior bats normally come with no warrantee.

Why find a sibling? Well, if you have a choice...I would choose something similar to your gamer. Why swing a 25 ounce balanced bat to practice...if your gamer is a 27 ounce half ounce end load? Obviously if you don't have a choice...swing anything...even a broom handle. That's what Ted Williams did when he was in off season and didn't have a bat.

No, USSSA/ASA/NSA bats typically are not as hot as senior bats. However, you still get excellent performance from them. If we can get past our own egos, we can swing the USSSA bats in all temperatures. Learn to hit homers with a USSSA/ASA/NSA bat...and hitting homers with a senior bat will be a walk in the park!

Yes, the DeMarini Flipper (ASA) is a great bat to swing. BTW...you can also use that bat in any SSUSA tournament as well. It may actually perform better than a senior bat if the ball being used is an ASA ball. As you probably know, there have been supply issues with the SSUSA Stote. Occasionally have seen an ASA ball used as an alternative. (44/375) An ASA bat and an ASA ball sound like a good strategy to me.

What we use for our BP session in cold weather, 300 compression 52 core softballs.