Cymbopogon narduus is citronella - I use a product containing this and I find it very effective against insect bites (and my male has allegies so I'm always looking for things that will help him). I'm told lavender can also be effective in controlling the itchiness associated with bites but I've not tried it directly.
We attended another Rally event this weekend - entered in Rally Masters: Gossip (almost 11 y) achieved a 97 and 98 (personal best); Teddy (almost 8 y) achieved a 99 (personal best) and 86 (wouldn't do the right spin). That gives them their 5th and 6th legs respectively - just love the color green
Formal training is definitely needed - but you need to find a trainer that is familiar with a number of different breeds (one of my first trainers was an aussie-shepherd person and never worked with hounds before - what a mistake that was).
If there are dog schools that offer the AKC Canine Good Citizen classes in your area, I'd consider these after you've taken basic obedience. Or ask about a "manners" class.
Forget the walks in crowded areas and forget the off-leash parks.
I also would not suggest the head-halters ("gentle leader") on basenjis - these dogs will suddenly "take off" towards a squirrel or other prey animal and the gentle-leader/head-halter can damage the neck (it works fine for dogs that are more people oriented).
Ditto Tanza's comments. Be consistent about taking him to potty (whether the litter box or ourside) and at regular intervals for now. When he does go, be sure to praise him (so he knows it's a good thing to go "when asked") and give a treat. Move the litter box to the doorway then to outside so he gets the idea - you can also train a particular area in the yard as well if desired. Always praise and or treat when he goes when you take him - that will help.
You might want to take advanced obedience classes - "mind your manners", "bogeyman", "impulse control" etc. if they are offered in your area
(Fenzi Dog Sports Academy offers such classes online also) or even a
competitive obedience novice level class. I found these sorts of classes
really helped my Teddy work more calmly around other dogs.
Never take mine to a groomer - as Tanza said they pretty much self groom - I brush in spring when their winter coat comes off. Quality food and maybe some fish oil supplement will help. If his skin is really dry you may need a shampoo (oatmeal based recommended by my vet).