Yes it is possible that landey/tappa as a very old form of poetry was assimilated by Pashtun culture/ language even 1000 yrs ago.First known Afghan landey was ccomposed at Mahmud of Ghazni's court by a sweetheart of one of Mahmud's generals.

Chaarbayta

Structure: Chaarbayta differ depending on the number and lenght of misra's. The number of misra's in one stanza varies from four to twenty. Each chaarbayta has a refrain called sar, kaser or piro. It appears in the beginning of the chaarbayta, and is repeated after each stanza. The content of sar is different after each stanza, only the rhyme is constant.
The structural pattern of the poem is the following:

b__________ b__________
a__________ a__________

a__________ a__________
c__________ c__________
d__________ d__________
e__________ e__________
f__________ f__________
a__________
a__________

g__________ g__________
h__________ h__________
i__________ i__________
j__________ j__________
k__________ k__________
a__________
a__________

Rhymes: The first line of the first stanza must rhyme with the refrain. Other stanzas may begin in any manner but the final bayt of each must rhyme with the refrain.

Topics: Usually one motif that should be developped.

Other features: Chaarbayta has the function of a ballad. Mainly used for tales and other themes requiring a longer form.

Xaanamir:
pe chap ke daal pe khe khanjar nisema
de ghalim mekha baraabar nisema
yaa ba sidka khpel watan shi zmaa
yaa ba pe sro winokafan shi zmaa

Perso-Arabic forms in Pashto poetry

Ghazal

Structure: First bayt of ghazal is called matla. Number of syllables in each hemistich is constant. Number of lines varies from five to fifteen.

Rhymes: Both hemistichs rhyme - it is a monorhyme poem.

Topic: Most ghazals are love-poems.

Other information: Very common form of poetry. First ghazal in Pashto language was written in 14th century. Early Pashto ghazals were very short, consisted of three to seven lines, they weren't as complex as ghazals from later centuries.

Perso-Arabic forms in Pashto poetry

Bolela (Arab. kasida)

Structure: The lenght of this form varies from sixteen to two hundred lines. Number of syllables is the same in each hemistich.

Rhymes: both hemistichs of the first bayt and all the second misra's of the remaining lines represent the same rhyme (monorhyme).

Topic: diverse.

Perso-Arabic forms in Pashto poetry

Masnawi

Structure: It is a polyrhyme verse. The number of lines can vary considerably, depending on the subject matter.

Rhymes: hemistichs rhyme in every bayt (not the first bayt only)

Topic: diverse.

Perso-Arabic forms in Pashto poetry

Kita

Structure: This form consists of two or more lines taken out of a poem of a bigger format.

Rhymes: First two hemistichs do not rhyme. All the second misra's of the ramaining lines have a common rhyme.

Topic: diverse.

andeshna ka pe ghre kij de
ghar ba ham leka wikhta kaa
khwaar saray malaamat na dey
ka pe gham kkhe jaan ube kaa

Perso-Arabic forms in Pashto poetry

Rubaai

Structure: It is a popular tetrastich. Its graphic presentation often differs from that of Persian rubaa'i, i.e. it is two bayts and not four misra's.

a__________ a__________
a__________ b__________

Rhymes: The first, the second and the fourth misra's rhym.

'umr mi trikh shu pe firaakat kkhe
oshe mi caaci tel pe hasrat kkhe
judaai or da pe zre lagegi
pe marg raazi yem na pe gharbat kkhe

Perso-Arabic forms in Pashto poetry

Mustazaad is a special type of verse in which every line is followed by a short complimentary line with its own rhyme pattern:

na hwag larem che waawrem na pe khola de khayr wayel krem
mudaam minnat per bel krem
che kahr raashi 'akl me maghlub shi no shkanzel krem
mudaam minnnat per bel krem

Does anyone know of any Pashto poetry workshops? I am guessing there might be some in Afghanistan or Pakistan.

By the way, Yasmeena khory, the way you are describing the structures of many of the poems is unclear.