You can’t really force your neighbor to put up a fence unless their fence is on violations of some code (for example most municipalities have rules about fences around pools and such). Even then the best you could do is report it to whatever force handles building code violations and then wait to see what they do (they may force the fence to be brought up to code or they could just charge a fine and allow it to stay as is).
What you can do, short of building a second fence, is put up a privacy screen or with permission modify it in some other way.
As for the jumping, you can take photos or videos and report it each time it happens. If you need to leave your dog outside unattended for whatever reason, a dog run may be a cheaper option than building a new fence entirely.
Here is an idea using artificial ivy. I don't know the quality, but it may be an option. Check with your association to make sure you can install it without breaking and rules/regs.
https://www.amazon.com/Best-Choice-Products-Artificial-Decoration/dp/B008QZSITG
NTA How tall is your fence? Is the cat jumping it? I’ve seen people put rollers on top that roll when an animal hops up so they can’t hop over. Idk what they are called but they are like pvc pipe on top that when the animal grabs it to jump it rolls back
They also make these spikes https://www.amazon.com/TheOutDoorShop-Repeller-Fence-wall-spikes/dp/B003ZYJO5A/ref=asc_df_B003ZYJO5A/?tag=hyprod-20&linkCode=df0&hvadid=222262841422&hvpos=&hvnetw=g&hvrand=1836069162654279487&hvpone=&hvptwo=&hvqmt=&...
Here is the cat fence thing
13 ft x 3 ft for $47, free shipping. If you click the "Used" options, Amazon also has a returned one with some minor cosmetic damage for $10 cheaper. But as I said in the other comment, check your strata.
IANAL but from what I just looked up. For booby trapping your home (Random nails hidden on the back side of your fence then filed down to cause harm will most likely qualify) can get you 2 to 5 years in a state prison.
http://ag.ca.gov/firearms/dwcl/12355.php/
You would be better off finding a decorative alternative or something like the amazon link below.
Consider something like this Faux Ivy Privacy Screen.
You wouldn't need to cover the whole wall, just the area that will be the backdrop for where you're taking the vows and staging pictures. Browse thrift stores for two tall fake potted plants to serve as "bookends" to really stage the spot. You can wire or hot-glue decorations to the "fence" and the "bookends" and even string lights thru them. An outdoor wedding with lots of green grass - fake greenery fits nicely. And bonus - it's something that can be used after the wedding (look at the customer pictures in the review section at the above link) so you could get away with not considering it a wedding expense but a "home improvement" one. ;)
There are many similar type products on Amazon, just search around and maybe you'll find something that suits you size & price wise.
They are building next door to us. The window is actually much larger than the tv, the angle of the picture just makes them look like a similar size.
I will get the panel link up soon, just waiting for my guy to get home since he placed the order. Promise it's coming!
Edit: Sorry for the delay. Here it is!
something like this privacy screen on your fence until the lilac grows back or new plants grow to maturity
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https://www.amazon.com/Windscreen4less-Privacy-Screen-Grommets-Warranty/dp/B00CEIKEP2
Farm fencing is never concreted in the ground. Its too costly to use and causes the posts to rot prematurely.
I think you’d have a very tedious and difficult task of drilling/chiseling out the old posts to reuse the footings.
Since you already have the footings, perhaps something like a fence post anchor base bracket would be more time/cost efficient.
You could use a post bracket similar to this https://www.amazon.com/MTB-Fence-Support-Powder-Coated/dp/B077SZMP7T. Screw it to the concrete with TapCon screws and attach a 4x4 post. Mount mailbox to post.
I bought this last year to cover a chainlink fence & it works & looks great https://www.amazon.com/gp/product/B00CEIKEP2/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
attached it with these: https://www.amazon.com/gp/product/B07W52Q3JN/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
MTB Fence Post Support Bolt Down Metal Black Powder Coated 4 Inch x 4 Inch (Inner Diameter 3.5 x3.5 Inches), Pack of 1 https://www.amazon.com/dp/B077SZMP7T/ref=cm_sw_r_cp_api_glt_fabc_10Z5XEMTYNSF37B6WPG1?_encoding=UTF8&psc=1
maybe look in to something like this
I ordered 'faux ivy privacy screen' from Amazon for my balcony and it's great. I can't figure out how to attach photos of mine here to show you, but you can't see anything through it at night and it blends in with my plants.
Mine literally just shove right into the ground. I have fairly heavy climbing roses on some of mine and they don’t wobble.
This is the kind I have. You just shove them in the ground and they stand up. They’re pretty cheap if you look around for wider ones.
Side by side you can anchor them to each other with zip ties for strength as well. They’re more than enough to support the fake ivy. It’s not heavy at all.
This is the sort of ivy I used. Not the same brand but there are tons on Amazon.
Just leave room for the meter reader to get in there without having to shove anything out of the way.
What I ended up doing because they really liked it out there was getting some reed siding, something like this, and using that to line the inside of the balcony railing so that they couldn't jump off. It looked nice enough, and they were able to be out on the balcony safely.
There are various privacy screens you can get for chain link fence, e.g. slat weaves or fabric sheets. Those won't prevent the neighbor from digging but they may prevent him from being tempted.