New RR/BMC Puppy parent lots of questions - need help Questions

Hello - I am new to the forum and a relatively new puppy parent. So just a little history: Both my husband and I had dogs growing up but we have been married for 20 years (no kids but 11 nieces and nephews ranging from 10 to 36). I had a poodle and then a Terrier, lhasa apso, Cocker Spaniel mix (Terriopsiocker - lol). My husband had a couple of mix breed but mainly beagles.

We have always talked about getting a dog but it just never seemed to work out til this year. Last spring we rescued a puppy we are guessing we are at least the 4th home she has been in and when she came to us she was 9 to 12 months old (best guess by the vet) she had not been spayed and probably didn't have her shots (both of which we did right away). We were told she was a lab / shepherd mix but the vet said no she is primarily a Rhodesian Ridgeback / Black Mouth Curr mix (RR/BMC) (with maybe some lab and shepherd but very little). She was also very thin and she went from 55lbs to 65lbs in the last 5 months. They also said she was 6 months, spayed and up on shots - also not true. Luckily the vet said she was very healthy and she was to our surprise she was kennel trained, somewhat leash trained (not loose leash but doesn't pull but definitely stays in front), she was house trained and doggy door trained. She knows sit and lay down and does those well but other commands not so much. She has NO food or toy aggression at all.

She is the sweetest thing and we love her like crazy and we are trying to keep her active with daily walks but she needs more exercise as she can be a bit rambunctious and high energy and we are not though we are slowly getting there. She is a chewer but only on her toys (only lost one pair of slippers and a uniform patch) though she has chewed just about any towel or blanket we put in her kennel or outside for her. The one we put on the couch for her she lays on but does not chew. She had destroyed most toys within minutes but have found the black kong toys are holding up as well as a kong football (purple). She does go through elk antlers in about 3 weeks.

1. I was thinking of getting her a big ball she can chase around but not be able to chew up - so my question is which would be better: Soccer ball, basketball, or volleyball? She has several indoor toys kongs etc but this would be outside only to chase around her pen during the day.

2. We finally got her pen (she is a jumper and can clear our 5 foot fence wall easily) complete She has not a huge area but room to play 16 feet by 17 feet and then access through her doggy door into her kennel - but now for the first time she is digging - not sure if this is just because it is new or if this is common with RR and BMC - any ideas of how to keep her from digging out?

3. Like I said she is super sweet but 4 days after we brought her home my husband took her for a walk and a neighbor's dog (a bulldog) attacked them. He was able to separate them and neither was hurt but now she is dog fearful but acts dog aggressive - are RR and or BMC typically dog friendly or not as an overall temperament? We have been trying to work with her but she just does not seem to be getting any better - we have to try and avoid other dogs when we go for our walks which is not easy - any ideas on how to get her at least dog tolerant? We know we probably need to have a trainer work with us but right now unfortunately cost is an issue.

4. Do RR and or BMC fur get darker as they age / get older? She seems to be getting slightly darker on the muzzle and a little on her belly - just want to know if this is normal or should I be worried and take her to the vet?

I am sure I will have lots of questions but any and all advice would be helpful.

Thank you all in advance - any tips or suggestions or encouragement would be greatly appreciated.

Mental stimulation as well as physical activity will tire her out.
Flirt poles are a great form of exercise and at the same time teaching self control.

The KONG Extreme Ball is pretty robust’

As for digging out of pen, best to sit it on top of concrete or slabs.

As for dog aggression keep at a distance that she is happy with and distract with toy food or bit of training, before she kicks off gradually working up to get nearer.