Trying now a fresh install without any updating, doing this in terminal first:
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(remember to also not tick the two boxes at the beginning of LXLE installing!)

Stop python-software-properties from upgrading via Synaptic
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Menu > System Tools > Synaptic Package Manager

Search for: python-software-properties

Make the package active.

Select from the top "Package" menu >

Tick "Lock Version".

Push "Reload" button.

Close and reopen Synaptic to update the system now.

Update and upgrade via Synaptic Package Manager
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http://lxle.net/forum/#/discussion/105/how-to-update-lxle-paradigm-use-synaptic-package-manager-

Synaptic provides two methods for upgrading your system.

    One easy way to upgrade your system with Synaptic:

        Click Reload or press Ctrl + R to make Synaptic aware of the latest updates.

        Click Mark all Upgrades or press Ctrl + G.

        Click Apply on the toolbar or press Ctrl + P. A dialog appears with a summary of the changes that will be made to your system.

        Click Apply to confirm the changes and go ahead with the upgrade.

Using the pre-configured Synaptic Package Manager guarantees that only
the updates LXLE needs are performed; whereas, using 'apt-get' in the
terminal allows new release upgrades which may not be LTS, nor may be compatible with certain 'spin' changes that LXLE incorporates.

Some wise info about dist-upgrade in terminal:

https://help.ubuntu.com/12.10/serverguide/installing-upgrading.html
http://askubuntu.com/questions/215267/will-apt-get-dist-upgrade-upgrade-my-system-to-newer-version
http://ubuntulinuxtipstricks.blogspot.com/2010/02/dist-upgrade-misnomer-confusion.html

And as for my personal info about updating now. I will try to use Synaptic Package Manager for it.

Be warned -- using Lock Package in SynapticPM only stays in effect if
you always use SynapticPM (recommended)...the lock is ignored otherwise
-- End of Warning but...

To lock or hold via terminal you should do:

sudo apt-mark hold <package-name>

OR

echo <package-name> hold | sudo dpkg --set-selections